Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/ec2-user/anaconda3/lib/python2.7/site-packages/pymodis/__init__.py", line 1, in <module>
    import downmodis, parsemodis, convertmodis, optparse_required
  File "/home/ec2-user/anaconda3/lib/python2.7/site-packages/pymodis/downmodis.py", line 42, in <module>
    raise('Python GDAL library not found, please install python-gdal')
TypeError: exceptions must be old-style classes or derived from BaseException, not str