code: def find_distinct(self, collection, key):
          
          obj = getattr(self.db, collection)
          result = obj.distinct(key)
          return result
docs: Search a collection for the distinct key values provided.
  
          Args:
              collection: The db collection. See main class documentation.
              key: The name of the key to find distinct values. For example with
                   the indicators collection, the key could be "type".
          Returns:
              List of distinct values.