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

def lists(self, column, key=None):
        """
        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
        """
        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