Right, this is defined in the `DissimilarityMatrix` baseclass, but it'll return an instance of whatever class this method is called on (currently `DissimilarityMatrix` or `DistanceMatrix`). The docstrings refer to dissimilarities because these methods are defined in `DissimilarityMatrix`, and we may not be storing distances (or whatever other matrix subclasses we might have in the future). The docstrings for `DistanceMatrix` refer to distances.

I'm not quite sure how to handle this- a `DistanceMatrix` is a `DissimilarityMatrix`, and both types of matrices use the same file format. I note this relationship in the module docstring, though I can see how that might be missed.

I can see the potential cause of confusion, but vote to change the docstring summary line back to what it was, since this method may not be parsing distances. Note that this problem also exists in the `BiologicalSequence` and `SequenceCollection` hierarchies. Anyone have ideas on how to handle this?

I agree that another test case should be added to `DistanceMatrixTests` to test that `from_file` returns the correct type if called on a subclass.