If the statement returns rows, a string of the results is returned.
        If the statement returns no rows, an empty string is returned.
        If the statement throws an error, the error message is returned.
        """
        try:
            from pyspark.errors import PySparkException
        except ImportError:
            raise ValueError(
                "pyspark is not installed. Please install it with `pip install pyspark`"
            )
        try:
            return self.run(command, fetch)
        except PySparkException as e:
            """Format the error message"""
            return f"Error: {e}"