"""
Unified place for determining if external dependencies are installed or not.

You should import all external modules using the import_module() function.

For example

>>> from sympy.external import import_module
>>> numpy = import_module('numpy')

If the resulting library is not installed, or if the installed version is less
than a given minimum version, the function will return None.  Otherwise, it will
return the library.  See the docstring of import_module() for more information.
"""

from importtools import import_module
