:~ luckydonald$ docker run -it --rm python:3.9 bash
root@49a5d339a9a5:/# pip install image-intensities
Collecting image-intensities
  Downloading image_intensities-0.0.7.tar.gz (447 kB)
     |████████████████████████████████| 447 kB 8.6 MB/s
  Installing build dependencies ... done
  Getting requirements to build wheel ... done
    Preparing wheel metadata ... done
Collecting cffi>=1.0.0
  Using cached cffi-1.14.6-cp39-cp39-manylinux1_x86_64.whl (405 kB)
Collecting luckydonald-utils>=0.73
  Using cached luckydonald_utils-0.83-py3-none-any.whl (82 kB)
Collecting pycparser
  Using cached pycparser-2.20-py2.py3-none-any.whl (112 kB)
Collecting DictObject
  Using cached DictObject-1.1.1-py3-none-any.whl
Requirement already satisfied: setuptools in /usr/local/lib/python3.9/site-packages (from luckydonald-utils>=0.73->image-intensities) (54.1.1)
Requirement already satisfied: pip in /usr/local/lib/python3.9/site-packages (from luckydonald-utils>=0.73->image-intensities) (21.0.1)
Building wheels for collected packages: image-intensities
  Building wheel for image-intensities (PEP 517) ... error
  ERROR: Command errored out with exit status 1:
   command: /usr/local/bin/python /usr/local/lib/python3.9/site-packages/pip/_vendor/pep517/_in_process.py build_wheel /tmp/tmp54010f2g
       cwd: /tmp/pip-install-67p_xgsw/image-intensities_9bb1019acecd4fdf85cc5375632f653e
  Complete output (130 lines):
  running bdist_wheel
  running build
  running build_py
  creating build
  creating build/lib.linux-x86_64-3.9
  creating build/lib.linux-x86_64-3.9/image_intensities
  copying image_intensities/build_cffi.py -> build/lib.linux-x86_64-3.9/image_intensities
  copying image_intensities/compiled_cffi.py -> build/lib.linux-x86_64-3.9/image_intensities
  copying image_intensities/native_ctypes.py -> build/lib.linux-x86_64-3.9/image_intensities
  copying image_intensities/__init__.py -> build/lib.linux-x86_64-3.9/image_intensities
  copying image_intensities/version.py -> build/lib.linux-x86_64-3.9/image_intensities
  copying image_intensities/native_cffi.py -> build/lib.linux-x86_64-3.9/image_intensities
  copying image_intensities/availability.py -> build/lib.linux-x86_64-3.9/image_intensities
  copying image_intensities/shared_cffi.py -> build/lib.linux-x86_64-3.9/image_intensities
  copying image_intensities/pure_python.py -> build/lib.linux-x86_64-3.9/image_intensities
  copying image_intensities/VERSION.txt -> build/lib.linux-x86_64-3.9/image_intensities
  copying image_intensities/compiled_cython.pyx -> build/lib.linux-x86_64-3.9/image_intensities
  copying image_intensities/build_cffi.c-files.txt -> build/lib.linux-x86_64-3.9/image_intensities
  copying image_intensities/build_cffi.h-files.txt -> build/lib.linux-x86_64-3.9/image_intensities
  creating build/lib.linux-x86_64-3.9/image_intensities/_native_code
  creating build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jsimd_none.c -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jchuff.c -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jcapimin.c -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jcapistd.c -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jccolor.c -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jcicc.c -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jccoefct.c -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jcinit.c -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jcdctmgr.c -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jcmainct.c -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jcmarker.c -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jcmaster.c -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jcomapi.c -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jcparam.c -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jcphuff.c -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jcprepct.c -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jcsample.c -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jctrans.c -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jdapimin.c -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jdapistd.c -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jdatadst.c -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jdatasrc.c -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jdcoefct.c -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jdcolor.c -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jddctmgr.c -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jdhuff.c -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jdicc.c -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jdinput.c -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jdmainct.c -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jdmarker.c -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jdmaster.c -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jdmerge.c -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jdphuff.c -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jdpostct.c -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jdsample.c -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jdtrans.c -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jerror.c -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jfdctflt.c -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jfdctfst.c -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jfdctint.c -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jidctflt.c -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jidctfst.c -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jidctint.c -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jidctred.c -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jquant1.c -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jquant2.c -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jutils.c -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jmemmgr.c -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jmemnobs.c -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jaricom.c -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jdarith.c -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jcarith.c -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/turbojpeg.c -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/transupp.c -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jdatadst-tj.c -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jdatasrc-tj.c -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/rdbmp.c -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/rdppm.c -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/wrbmp.c -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/wrppm.c -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/intensities.c -> build/lib.linux-x86_64-3.9/image_intensities/_native_code
  copying image_intensities/_native_code/png.c -> build/lib.linux-x86_64-3.9/image_intensities/_native_code
  copying image_intensities/_native_code/jpeg.c -> build/lib.linux-x86_64-3.9/image_intensities/_native_code
  copying image_intensities/_native_code/turbojpeg/cderror.h -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/cdjpeg.h -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/cmyk.h -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jchuff.h -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jconfigint.h -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jconfig.h -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jdcoefct.h -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jdhuff.h -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jdmainct.h -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jdmaster.h -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jdsample.h -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jerror.h -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jinclude.h -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jmemsys.h -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jmorecfg.h -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jpeg_nbits_table.h -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jpegcomp.h -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jpegint.h -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jpeglib.h -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jsimd.h -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jsimddct.h -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/jversion.h -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/tjutil.h -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/transupp.h -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/turbojpeg/turbojpeg.h -> build/lib.linux-x86_64-3.9/image_intensities/_native_code/turbojpeg
  copying image_intensities/_native_code/definitions.h -> build/lib.linux-x86_64-3.9/image_intensities/_native_code
  running build_ext
  generating cffi module 'build/temp.linux-x86_64-3.9/image_intensities._native_code._image_intensities.c'
  creating build/temp.linux-x86_64-3.9
  building 'image_intensities.compiled_cython' extension
  creating build/temp.linux-x86_64-3.9/image_intensities
  gcc -pthread -Wno-unused-result -Wsign-compare -DNDEBUG -g -fwrapv -O3 -Wall -fPIC -I/usr/local/include/python3.9 -c image_intensities/compiled_cython.c -o build/temp.linux-x86_64-3.9/image_intensities/compiled_cython.o
  gcc -pthread -shared build/temp.linux-x86_64-3.9/image_intensities/compiled_cython.o -L/usr/local/lib -o build/lib.linux-x86_64-3.9/image_intensities/compiled_cython.cpython-39-x86_64-linux-gnu.so
  building 'image_intensities.pure_python' extension
  gcc -pthread -Wno-unused-result -Wsign-compare -DNDEBUG -g -fwrapv -O3 -Wall -fPIC -I/usr/local/include/python3.9 -c image_intensities/pure_python.c -o build/temp.linux-x86_64-3.9/image_intensities/pure_python.o
  gcc -pthread -shared build/temp.linux-x86_64-3.9/image_intensities/pure_python.o -L/usr/local/lib -o build/lib.linux-x86_64-3.9/image_intensities/pure_python.cpython-39-x86_64-linux-gnu.so
  building 'image_intensities._native_code._image_intensities' extension
  creating build/temp.linux-x86_64-3.9/_native_code
  creating build/temp.linux-x86_64-3.9/_native_code/turbojpeg
  creating build/temp.linux-x86_64-3.9/build
  creating build/temp.linux-x86_64-3.9/build/temp.linux-x86_64-3.9
  gcc -pthread -Wno-unused-result -Wsign-compare -DNDEBUG -g -fwrapv -O3 -Wall -fPIC -I./_native_code/turbojpeg -I./_native_code -I/usr/local/include/python3.9 -c ./_native_code/intensities.c -o build/temp.linux-x86_64-3.9/./_native_code/intensities.o -std=c99 -fPIC -O3 -DPPM_SUPPORTED -DBMP_SUPPORTED
  gcc: error: ./_native_code/intensities.c: No such file or directory
  gcc: fatal error: no input files
  compilation terminated.
  error: command '/usr/bin/gcc' failed with exit code 1
  ----------------------------------------
  ERROR: Failed building wheel for image-intensities
Failed to build image-intensities
ERROR: Could not build wheels for image-intensities which use PEP 517 and cannot be installed directly
WARNING: You are using pip version 21.0.1; however, version 21.2.2 is available.
You should consider upgrading via the '/usr/local/bin/python -m pip install --upgrade pip' command.
root@49a5d339a9a5:/#