remove extend_path from all internal __init__ files

bob/learn/pytorch/__init__.py

-# see https://docs.python.org/3/library/pkgutil.html
-from pkgutil import extend_path
-__path__ = extend_path(__path__, __name__)
 
 # gets sphinx autodoc done right - don't remove it
 def __appropriate__(*args):

bob/learn/pytorch/extractor/__init__.py

-# see https://docs.python.org/3/library/pkgutil.html
-from pkgutil import extend_path
-__path__ = extend_path(__path__, __name__)
 
 # gets sphinx autodoc done right - don't remove it
 def __appropriate__(*args):

bob/learn/pytorch/preprocessor/__init__.py

-# see https://docs.python.org/3/library/pkgutil.html
 
 # gets sphinx autodoc done right - don't remove it
 def __appropriate__(*args):