code: def fill_missing_fields(self, data, columns):
          
  
          for column in columns:
              if column not in data.columns:
                  data[column] = scipy.zeros(len(data))
  
          return data
docs: 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