def __eq__(self, other):
return self._index == other._index<EOL>
determine whether two IndexedFile objects are equal. To be so, the index
dictionaries themselves must be equal. We will not compare filename;
basically, we don't care where the index information came from or whether
it might cease to be equal later, as long as the actual index itself is
the same.

:param other: the other IndexedFile to compare against.