In Python 3.3, python namespace packages were introduced [0] - namespace package is a virtual package whose contents can be distributed in various places along Python's PATH. TL;DR

Currently importing a namespace package in bpython fails with:

>>> import my_namespace
Traceback (most recent call last):
  File "<input>", line 1, in <module>
    import my_namespace
ModuleNotFoundError: No module named 'my_namespace'

whereas the identical python distribution, just running native shell, produces:

>>> import my_namespace
>>> my_namespace
<module 'my_namespace' (namespace)> 

[0] https://www.python.org/dev/peps/pep-0420/