@mdboom - if you do this check with equivalencies, do also update the `docstring`, as it currently states:
```
        other : unit object or string or tuple
            The unit to convert to. If a tuple of units is specified, this
            method returns true if the unit matches any of those in the tuple;
            for this case, equivalencies are ignored.
```
(I added it there a while back, changing the docs to match what was done, but I guess I should have asked what the desired behaviour was!)