code: def _utf8_encode(self, d):
          
          for k, v in d.items():
              if isinstance(v, str):
                  d[k] = v.encode('utf8').lower()
              if isinstance(v, list):
                  for index,item in enumerate(v):
                      item = item.encode('utf8').lower()
                      v[index] = item
              if isinstance(v, dict):
                  d[k] = self._utf8_encode(v)
          
          return d
docs: Ensures all values are encoded in UTF-8 and converts them to lowercase