def fill_missing_fields(self, data, columns):
        """ This  method fills with 0's missing fields

        :param data: original Pandas dataframe
        :param columns: list of columns to be filled in the DataFrame
        :type data: pandas.DataFrame
        :type columns: list of strings

        :returns: Pandas dataframe with missing fields filled with 0's
        :rtype: pandas.DataFrame
        """

        for column in columns:
            if column not in data.columns:
                data[column] = scipy.zeros(len(data))

        return data
This  method fills with 0's missing fields

        :param data: original Pandas dataframe
        :param columns: list of columns to be filled in the DataFrame
        :type data: pandas.DataFrame
        :type columns: list of strings

        :returns: Pandas dataframe with missing fields filled with 0's
        :rtype: pandas.DataFrame