code: def lists(self, column, key=None):
          
          columns = self._get_list_select(column, key)
  
          if key is not None:
              results = {}
              for result in self.get(columns):
                  results[result[key]] = result[column]
          else:
              results = Collection(list(map(lambda x: x[column], self.get(columns))))
  
          return results
docs: Get a list with the values of a given column
  
          :param column: The column to get the values for
          :type column: str
  
          :param key: The key
          :type key: str
  
          :return: The list of values
          :rtype: Collection or dict