code: def enrich(self, column1, column2):
          
  
          if column1 not in self.commits.columns or \
             column2 not in self.commits.columns:
              return self.commits
  
          # Select rows where values in column1 are different from
          # values in column2
          pair_df = self.commits[self.commits[column1] != self.commits[column2]]
          new_values = list(pair_df[column2])
          # Update values from column2
          pair_df[column1] = new_values
  
          # This adds at the end of the original dataframe those rows duplicating
          # information and updating the values in column1
          return self.commits.append(pair_df)
docs: This class splits those commits where column1 and column2
          values are different
  
          :param column1: column to compare to column2
          :param column2: column to compare to column1
          :type column1: string
          :type column2: string
  
          :returns: self.commits with duplicated rows where the values at
              columns are different. The original row remains while the second
              row contains in column1 and 2 the value of column2.
          :rtype: pandas.DataFrame