def modified_from_status(status_out):
    """ Return a generator of modified files from git status output.

    The output is expected to be in the format returned by
    ``git status --porcelain``
    """
    stripped = (ln.strip() for ln in status_out.split('\n'))
    modded = (ln for ln in stripped if ln.startswith('M'))
    return (ln.split()[1] for ln in modded)