def register(self, key, **kwargs):
dimensions = dict((k, str(v)) for k, v in kwargs.items())<EOL>composite_key = self._composite_name(key, dimensions)<EOL>self._metadata[composite_key] = {<EOL>'<STR_LIT>': key,<EOL>'<STR_LIT>': dimensions<EOL>}<EOL>return composite_key<EOL>
Registers metadata for a metric and returns a composite key