Loads contents of the tables into database.

def load_contents(self):
        """
            Loads contents of the tables into database.
        """
        with open(METADATA_FILE) as f:
            lines = f.readlines()

        lines = map(lambda x: x.strip(), lines)

        exclude_strings = ['<begin_table>', '<end_table>']

        list_of_databases_and_columns = filter(
            lambda x: not x[0] in exclude_strings, [
                list(value) for key, value in itertools.groupby(
                    lines,
                    lambda x: x in exclude_strings
                )
            ]
        )

        for iterator in list_of_databases_and_columns:
            self.create_table_raw(
                tablename=iterator[0],
                columns=iterator[1:][:],
            )

        for i in self.tables:
            i.load_contents()