Error: [NbConvertApp] Converting notebook chap06.ipynb to pdf
/srv/conda/envs/notebook/lib/python3.7/site-packages/nbconvert/utils/pandoc.py:52: RuntimeWarning: You are using an unsupported version of pandoc (2.7.3).
Your version must be at least (1.12.1) but less than (2.0.0).
Refer to http://pandoc.org/installing.html.
Continuing with doubts...
  check_pandoc_version()
/srv/conda/envs/notebook/lib/python3.7/site-packages/nbconvert/utils/pandoc.py:52: RuntimeWarning: You are using an unsupported version of pandoc (2.7.3).
Your version must be at least (1.12.1) but less than (2.0.0).
Refer to http://pandoc.org/installing.html.
Continuing with doubts...
  check_pandoc_version()
/srv/conda/envs/notebook/lib/python3.7/site-packages/nbconvert/utils/pandoc.py:52: RuntimeWarning: You are using an unsupported version of pandoc (2.7.3).
Your version must be at least (1.12.1) but less than (2.0.0).
Refer to http://pandoc.org/installing.html.
Continuing with doubts...
  check_pandoc_version()
/srv/conda/envs/notebook/lib/python3.7/site-packages/nbconvert/utils/pandoc.py:52: RuntimeWarning: You are using an unsupported version of pandoc (2.7.3).
Your version must be at least (1.12.1) but less than (2.0.0).
Refer to http://pandoc.org/installing.html.
Continuing with doubts...
  check_pandoc_version()
/srv/conda/envs/notebook/lib/python3.7/site-packages/nbconvert/utils/pandoc.py:52: RuntimeWarning: You are using an unsupported version of pandoc (2.7.3).
Your version must be at least (1.12.1) but less than (2.0.0).
Refer to http://pandoc.org/installing.html.
Continuing with doubts...
  check_pandoc_version()
/srv/conda/envs/notebook/lib/python3.7/site-packages/nbconvert/utils/pandoc.py:52: RuntimeWarning: You are using an unsupported version of pandoc (2.7.3).
Your version must be at least (1.12.1) but less than (2.0.0).
Refer to http://pandoc.org/installing.html.
Continuing with doubts...
  check_pandoc_version()
/srv/conda/envs/notebook/lib/python3.7/site-packages/nbconvert/utils/pandoc.py:52: RuntimeWarning: You are using an unsupported version of pandoc (2.7.3).
Your version must be at least (1.12.1) but less than (2.0.0).
Refer to http://pandoc.org/installing.html.
Continuing with doubts...
  check_pandoc_version()
/srv/conda/envs/notebook/lib/python3.7/site-packages/nbconvert/utils/pandoc.py:52: RuntimeWarning: You are using an unsupported version of pandoc (2.7.3).
Your version must be at least (1.12.1) but less than (2.0.0).
Refer to http://pandoc.org/installing.html.
Continuing with doubts...
  check_pandoc_version()
/srv/conda/envs/notebook/lib/python3.7/site-packages/nbconvert/utils/pandoc.py:52: RuntimeWarning: You are using an unsupported version of pandoc (2.7.3).
Your version must be at least (1.12.1) but less than (2.0.0).
Refer to http://pandoc.org/installing.html.
Continuing with doubts...
  check_pandoc_version()
/srv/conda/envs/notebook/lib/python3.7/site-packages/nbconvert/utils/pandoc.py:52: RuntimeWarning: You are using an unsupported version of pandoc (2.7.3).
Your version must be at least (1.12.1) but less than (2.0.0).
Refer to http://pandoc.org/installing.html.
Continuing with doubts...
  check_pandoc_version()
/srv/conda/envs/notebook/lib/python3.7/site-packages/nbconvert/utils/pandoc.py:52: RuntimeWarning: You are using an unsupported version of pandoc (2.7.3).
Your version must be at least (1.12.1) but less than (2.0.0).
Refer to http://pandoc.org/installing.html.
Continuing with doubts...
  check_pandoc_version()
/srv/conda/envs/notebook/lib/python3.7/site-packages/nbconvert/utils/pandoc.py:52: RuntimeWarning: You are using an unsupported version of pandoc (2.7.3).
Your version must be at least (1.12.1) but less than (2.0.0).
Refer to http://pandoc.org/installing.html.
Continuing with doubts...
  check_pandoc_version()
/srv/conda/envs/notebook/lib/python3.7/site-packages/nbconvert/utils/pandoc.py:52: RuntimeWarning: You are using an unsupported version of pandoc (2.7.3).
Your version must be at least (1.12.1) but less than (2.0.0).
Refer to http://pandoc.org/installing.html.
Continuing with doubts...
  check_pandoc_version()
/srv/conda/envs/notebook/lib/python3.7/site-packages/nbconvert/utils/pandoc.py:52: RuntimeWarning: You are using an unsupported version of pandoc (2.7.3).
Your version must be at least (1.12.1) but less than (2.0.0).
Refer to http://pandoc.org/installing.html.
Continuing with doubts...
  check_pandoc_version()
/srv/conda/envs/notebook/lib/python3.7/site-packages/nbconvert/utils/pandoc.py:52: RuntimeWarning: You are using an unsupported version of pandoc (2.7.3).
Your version must be at least (1.12.1) but less than (2.0.0).
Refer to http://pandoc.org/installing.html.
Continuing with doubts...
  check_pandoc_version()
/srv/conda/envs/notebook/lib/python3.7/site-packages/nbconvert/utils/pandoc.py:52: RuntimeWarning: You are using an unsupported version of pandoc (2.7.3).
Your version must be at least (1.12.1) but less than (2.0.0).
Refer to http://pandoc.org/installing.html.
Continuing with doubts...
  check_pandoc_version()
/srv/conda/envs/notebook/lib/python3.7/site-packages/nbconvert/utils/pandoc.py:52: RuntimeWarning: You are using an unsupported version of pandoc (2.7.3).
Your version must be at least (1.12.1) but less than (2.0.0).
Refer to http://pandoc.org/installing.html.
Continuing with doubts...
  check_pandoc_version()
/srv/conda/envs/notebook/lib/python3.7/site-packages/nbconvert/utils/pandoc.py:52: RuntimeWarning: You are using an unsupported version of pandoc (2.7.3).
Your version must be at least (1.12.1) but less than (2.0.0).
Refer to http://pandoc.org/installing.html.
Continuing with doubts...
  check_pandoc_version()
/srv/conda/envs/notebook/lib/python3.7/site-packages/nbconvert/utils/pandoc.py:52: RuntimeWarning: You are using an unsupported version of pandoc (2.7.3).
Your version must be at least (1.12.1) but less than (2.0.0).
Refer to http://pandoc.org/installing.html.
Continuing with doubts...
  check_pandoc_version()
/srv/conda/envs/notebook/lib/python3.7/site-packages/nbconvert/utils/pandoc.py:52: RuntimeWarning: You are using an unsupported version of pandoc (2.7.3).
Your version must be at least (1.12.1) but less than (2.0.0).
Refer to http://pandoc.org/installing.html.
Continuing with doubts...
  check_pandoc_version()
/srv/conda/envs/notebook/lib/python3.7/site-packages/nbconvert/utils/pandoc.py:52: RuntimeWarning: You are using an unsupported version of pandoc (2.7.3).
Your version must be at least (1.12.1) but less than (2.0.0).
Refer to http://pandoc.org/installing.html.
Continuing with doubts...
  check_pandoc_version()
/srv/conda/envs/notebook/lib/python3.7/site-packages/nbconvert/utils/pandoc.py:52: RuntimeWarning: You are using an unsupported version of pandoc (2.7.3).
Your version must be at least (1.12.1) but less than (2.0.0).
Refer to http://pandoc.org/installing.html.
Continuing with doubts...
  check_pandoc_version()
/srv/conda/envs/notebook/lib/python3.7/site-packages/nbconvert/utils/pandoc.py:52: RuntimeWarning: You are using an unsupported version of pandoc (2.7.3).
Your version must be at least (1.12.1) but less than (2.0.0).
Refer to http://pandoc.org/installing.html.
Continuing with doubts...
  check_pandoc_version()
/srv/conda/envs/notebook/lib/python3.7/site-packages/nbconvert/utils/pandoc.py:52: RuntimeWarning: You are using an unsupported version of pandoc (2.7.3).
Your version must be at least (1.12.1) but less than (2.0.0).
Refer to http://pandoc.org/installing.html.
Continuing with doubts...
  check_pandoc_version()
/srv/conda/envs/notebook/lib/python3.7/site-packages/nbconvert/utils/pandoc.py:52: RuntimeWarning: You are using an unsupported version of pandoc (2.7.3).
Your version must be at least (1.12.1) but less than (2.0.0).
Refer to http://pandoc.org/installing.html.
Continuing with doubts...
  check_pandoc_version()
/srv/conda/envs/notebook/lib/python3.7/site-packages/nbconvert/utils/pandoc.py:52: RuntimeWarning: You are using an unsupported version of pandoc (2.7.3).
Your version must be at least (1.12.1) but less than (2.0.0).
Refer to http://pandoc.org/installing.html.
Continuing with doubts...
  check_pandoc_version()
/srv/conda/envs/notebook/lib/python3.7/site-packages/nbconvert/utils/pandoc.py:52: RuntimeWarning: You are using an unsupported version of pandoc (2.7.3).
Your version must be at least (1.12.1) but less than (2.0.0).
Refer to http://pandoc.org/installing.html.
Continuing with doubts...
  check_pandoc_version()
/srv/conda/envs/notebook/lib/python3.7/site-packages/nbconvert/utils/pandoc.py:52: RuntimeWarning: You are using an unsupported version of pandoc (2.7.3).
Your version must be at least (1.12.1) but less than (2.0.0).
Refer to http://pandoc.org/installing.html.
Continuing with doubts...
  check_pandoc_version()
/srv/conda/envs/notebook/lib/python3.7/site-packages/nbconvert/utils/pandoc.py:52: RuntimeWarning: You are using an unsupported version of pandoc (2.7.3).
Your version must be at least (1.12.1) but less than (2.0.0).
Refer to http://pandoc.org/installing.html.
Continuing with doubts...
  check_pandoc_version()
/srv/conda/envs/notebook/lib/python3.7/site-packages/nbconvert/utils/pandoc.py:52: RuntimeWarning: You are using an unsupported version of pandoc (2.7.3).
Your version must be at least (1.12.1) but less than (2.0.0).
Refer to http://pandoc.org/installing.html.
Continuing with doubts...
  check_pandoc_version()
/srv/conda/envs/notebook/lib/python3.7/site-packages/nbconvert/utils/pandoc.py:52: RuntimeWarning: You are using an unsupported version of pandoc (2.7.3).
Your version must be at least (1.12.1) but less than (2.0.0).
Refer to http://pandoc.org/installing.html.
Continuing with doubts...
  check_pandoc_version()
/srv/conda/envs/notebook/lib/python3.7/site-packages/nbconvert/utils/pandoc.py:52: RuntimeWarning: You are using an unsupported version of pandoc (2.7.3).
Your version must be at least (1.12.1) but less than (2.0.0).
Refer to http://pandoc.org/installing.html.
Continuing with doubts...
  check_pandoc_version()
/srv/conda/envs/notebook/lib/python3.7/site-packages/nbconvert/utils/pandoc.py:52: RuntimeWarning: You are using an unsupported version of pandoc (2.7.3).
Your version must be at least (1.12.1) but less than (2.0.0).
Refer to http://pandoc.org/installing.html.
Continuing with doubts...
  check_pandoc_version()
/srv/conda/envs/notebook/lib/python3.7/site-packages/nbconvert/utils/pandoc.py:52: RuntimeWarning: You are using an unsupported version of pandoc (2.7.3).
Your version must be at least (1.12.1) but less than (2.0.0).
Refer to http://pandoc.org/installing.html.
Continuing with doubts...
  check_pandoc_version()
/srv/conda/envs/notebook/lib/python3.7/site-packages/nbconvert/utils/pandoc.py:52: RuntimeWarning: You are using an unsupported version of pandoc (2.7.3).
Your version must be at least (1.12.1) but less than (2.0.0).
Refer to http://pandoc.org/installing.html.
Continuing with doubts...
  check_pandoc_version()
/srv/conda/envs/notebook/lib/python3.7/site-packages/nbconvert/utils/pandoc.py:52: RuntimeWarning: You are using an unsupported version of pandoc (2.7.3).
Your version must be at least (1.12.1) but less than (2.0.0).
Refer to http://pandoc.org/installing.html.
Continuing with doubts...
  check_pandoc_version()
/srv/conda/envs/notebook/lib/python3.7/site-packages/nbconvert/utils/pandoc.py:52: RuntimeWarning: You are using an unsupported version of pandoc (2.7.3).
Your version must be at least (1.12.1) but less than (2.0.0).
Refer to http://pandoc.org/installing.html.
Continuing with doubts...
  check_pandoc_version()
/srv/conda/envs/notebook/lib/python3.7/site-packages/nbconvert/utils/pandoc.py:52: RuntimeWarning: You are using an unsupported version of pandoc (2.7.3).
Your version must be at least (1.12.1) but less than (2.0.0).
Refer to http://pandoc.org/installing.html.
Continuing with doubts...
  check_pandoc_version()
/srv/conda/envs/notebook/lib/python3.7/site-packages/nbconvert/utils/pandoc.py:52: RuntimeWarning: You are using an unsupported version of pandoc (2.7.3).
Your version must be at least (1.12.1) but less than (2.0.0).
Refer to http://pandoc.org/installing.html.
Continuing with doubts...
  check_pandoc_version()
/srv/conda/envs/notebook/lib/python3.7/site-packages/nbconvert/utils/pandoc.py:52: RuntimeWarning: You are using an unsupported version of pandoc (2.7.3).
Your version must be at least (1.12.1) but less than (2.0.0).
Refer to http://pandoc.org/installing.html.
Continuing with doubts...
  check_pandoc_version()
/srv/conda/envs/notebook/lib/python3.7/site-packages/nbconvert/utils/pandoc.py:52: RuntimeWarning: You are using an unsupported version of pandoc (2.7.3).
Your version must be at least (1.12.1) but less than (2.0.0).
Refer to http://pandoc.org/installing.html.
Continuing with doubts...
  check_pandoc_version()
/srv/conda/envs/notebook/lib/python3.7/site-packages/nbconvert/utils/pandoc.py:52: RuntimeWarning: You are using an unsupported version of pandoc (2.7.3).
Your version must be at least (1.12.1) but less than (2.0.0).
Refer to http://pandoc.org/installing.html.
Continuing with doubts...
  check_pandoc_version()
/srv/conda/envs/notebook/lib/python3.7/site-packages/nbconvert/utils/pandoc.py:52: RuntimeWarning: You are using an unsupported version of pandoc (2.7.3).
Your version must be at least (1.12.1) but less than (2.0.0).
Refer to http://pandoc.org/installing.html.
Continuing with doubts...
  check_pandoc_version()
/srv/conda/envs/notebook/lib/python3.7/site-packages/nbconvert/utils/pandoc.py:52: RuntimeWarning: You are using an unsupported version of pandoc (2.7.3).
Your version must be at least (1.12.1) but less than (2.0.0).
Refer to http://pandoc.org/installing.html.
Continuing with doubts...
  check_pandoc_version()
/srv/conda/envs/notebook/lib/python3.7/site-packages/nbconvert/utils/pandoc.py:52: RuntimeWarning: You are using an unsupported version of pandoc (2.7.3).
Your version must be at least (1.12.1) but less than (2.0.0).
Refer to http://pandoc.org/installing.html.
Continuing with doubts...
  check_pandoc_version()
/srv/conda/envs/notebook/lib/python3.7/site-packages/nbconvert/utils/pandoc.py:52: RuntimeWarning: You are using an unsupported version of pandoc (2.7.3).
Your version must be at least (1.12.1) but less than (2.0.0).
Refer to http://pandoc.org/installing.html.
Continuing with doubts...
  check_pandoc_version()
/srv/conda/envs/notebook/lib/python3.7/site-packages/nbconvert/utils/pandoc.py:52: RuntimeWarning: You are using an unsupported version of pandoc (2.7.3).
Your version must be at least (1.12.1) but less than (2.0.0).
Refer to http://pandoc.org/installing.html.
Continuing with doubts...
  check_pandoc_version()
/srv/conda/envs/notebook/lib/python3.7/site-packages/nbconvert/utils/pandoc.py:52: RuntimeWarning: You are using an unsupported version of pandoc (2.7.3).
Your version must be at least (1.12.1) but less than (2.0.0).
Refer to http://pandoc.org/installing.html.
Continuing with doubts...
  check_pandoc_version()
[NbConvertApp] Writing 34206 bytes to ./notebook.tex
[NbConvertApp] Building PDF
Traceback (most recent call last):
  File "/srv/conda/envs/notebook/bin/jupyter-nbconvert", line 10, in <module>
    sys.exit(main())
  File "/srv/conda/envs/notebook/lib/python3.7/site-packages/jupyter_core/application.py", line 266, in launch_instance
    return super(JupyterApp, cls).launch_instance(argv=argv, **kwargs)
  File "/srv/conda/envs/notebook/lib/python3.7/site-packages/traitlets/config/application.py", line 658, in launch_instance
    app.start()
  File "/srv/conda/envs/notebook/lib/python3.7/site-packages/nbconvert/nbconvertapp.py", line 337, in start
    self.convert_notebooks()
  File "/srv/conda/envs/notebook/lib/python3.7/site-packages/nbconvert/nbconvertapp.py", line 507, in convert_notebooks
    self.convert_single_notebook(notebook_filename)
  File "/srv/conda/envs/notebook/lib/python3.7/site-packages/nbconvert/nbconvertapp.py", line 478, in convert_single_notebook
    output, resources = self.export_single_notebook(notebook_filename, resources, input_buffer=input_buffer)
  File "/srv/conda/envs/notebook/lib/python3.7/site-packages/nbconvert/nbconvertapp.py", line 407, in export_single_notebook
    output, resources = self.exporter.from_filename(notebook_filename, resources=resources)
  File "/srv/conda/envs/notebook/lib/python3.7/site-packages/nbconvert/exporters/exporter.py", line 178, in from_filename
    return self.from_file(f, resources=resources, **kw)
  File "/srv/conda/envs/notebook/lib/python3.7/site-packages/nbconvert/exporters/exporter.py", line 196, in from_file
    return self.from_notebook_node(nbformat.read(file_stream, as_version=4), resources=resources, **kw)
  File "/srv/conda/envs/notebook/lib/python3.7/site-packages/nbconvert/exporters/pdf.py", line 171, in from_notebook_node
    rc = self.run_latex(tex_file)
  File "/srv/conda/envs/notebook/lib/python3.7/site-packages/nbconvert/exporters/pdf.py", line 143, in run_latex
    self.latex_count, log_error)
  File "/srv/conda/envs/notebook/lib/python3.7/site-packages/nbconvert/exporters/pdf.py", line 105, in run_command
    "at {link}.".format(formatter=command_list[0], link=link))
OSError: xelatex not found on PATH, if you have not installed xelatex you may need to do so. Find further instructions at https://nbconvert.readthedocs.io/en/latest/install.html#installing-tex.