code: def update_dimension(self, key, value, description=None,
                           custom_properties=None, tags=None, **kwargs):
          
          data = {'description': description or '',
                  'customProperties': custom_properties or {},
                  'tags': tags or [],
                  'key': key,
                  'value': value}
          resp = self._put(self._u(self._DIMENSION_ENDPOINT_SUFFIX, key, value),
                           data=data, **kwargs)
          resp.raise_for_status()
          return resp.json()
docs: update a dimension
          Args:
              key (string): key of the dimension
              value (string): value of the dimension
              description (optional[string]): a description
              custom_properties (optional[dict]): dictionary of custom properties
              tags (optional[list of strings]): list of tags associated with
                  metric