code: def sql(self, query):
          
          return DataFrame.from_spark_rdd(self.sql_ctx.sql(query), self.sql_ctx)
docs: Perform a SQL query and create a L{DataFrame} of the result.
          The SQL query is run using Spark SQL. This is not intended for
          querying arbitrary databases, but rather querying Spark SQL tables.
          Parameters
          ----------
          query: string
              The SQL query to pass to Spark SQL to execute.
          Returns
          -------
          Sparkling Pandas DataFrame.