def METHOD_NAME(self, options, pattern):
    # type: (Values, str) -> List[str]
    wheel_dir = self._wheels_cache_dir(options)
    # The wheel filename format, as specified in PEP 427, is:
    #     {distribution}-{version}(-{build})?-{python}-{abi}-{platform}.whl
    #
    # Additionally, non-alphanumeric values in the distribution are
    # normalized to underscores (_), meaning hyphens can never occur
    # before `-{version}`.
    #
    # Given that information:
    # - If the pattern we're given contains a hyphen (-), the user is
    #   providing at least the version. Thus, we can just append `*.whl`
    #   to match the rest of it.
    # - If the pattern we're given doesn't contain a hyphen (-), the
    #   user is only providing the name. Thus, we append `-*.whl` to
    #   match the hyphen before the version, followed by anything else.
    #
    # PEP 427: https://www.python.org/dev/peps/pep-0427/
    pattern = pattern + ("*.whl" if "-" in pattern else "-*.whl")
    return filesystem.find_files(wheel_dir, pattern)