'Recompute this distribution\'s dependencies.'

def _compute_dependencies(self):

    from _markerlib import compile as compile_marker
    dm = self.__dep_map = {None: []}
    reqs = []
    for req in (self._parsed_pkg_info.get_all('Requires-Dist') or []):
        (distvers, mark) = self._preparse_requirement(req)
        parsed = next(parse_requirements(distvers))
        parsed.marker_fn = compile_marker(mark)
        reqs.append(parsed)
    def reqs_for_extra(extra):
        for req in reqs:
            if req.marker_fn(override={'extra': extra}):
                (yield req)
    common = frozenset(reqs_for_extra(None))
    dm[None].extend(common)
    for extra in (self._parsed_pkg_info.get_all('Provides-Extra') or []):
        extra = safe_extra(extra.strip())
        dm[extra] = list((frozenset(reqs_for_extra(extra)) - common))
    return dm
