def requires(self,extras=()):
dm = self._dep_map<EOL>deps = []<EOL>deps.extend(dm.get(None,()))<EOL>for ext in extras:<EOL><INDENT>try:<EOL><INDENT>deps.extend(dm[safe_extra(ext)])<EOL><DEDENT>except KeyError:<EOL><INDENT>raise UnknownExtra(<EOL>"<STR_LIT>" % (self, ext)<EOL>)<EOL><DEDENT><DEDENT>return deps<EOL>
List of Requirements needed for this distro if `extras` are used