Remove getCallback indirection in modules
Instead, assume that the imported module contains the Callback class
that was previously returned by getCallback. This is done to prevent
a circular import (caused by the __init__ importing a submodule).
# Until model subclassing is a possibility, a mixin class is used to add
# the necessary functions that may be contributed for geographic objects.
class GeoMixin:
"""
The Geographic Mixin class provides routines for geographic objects,
however, it is no longer necessary, since all of its previous functions
may now be accessed via the GeometryProxy. This mixin is only provided
for backwards-compatibility purposes, and will be eventually removed
(unless the need arises again).
"""
pass