code: def validate_set_ops(df, other):
      
  
      if df.columns.values.tolist() != other.columns.values.tolist():
          not_in_df = [col for col in other.columns if col not in df.columns]
          not_in_other = [col for col in df.columns if col not in other.columns]
          error_string = 'Error: not compatible.'
          if len(not_in_df):
              error_string += ' Cols in y but not x: ' + str(not_in_df) + '.'
          if len(not_in_other):
              error_string += ' Cols in x but not y: ' + str(not_in_other) + '.'
          raise ValueError(error_string)
      if len(df.index.names) != len(other.index.names):
          raise ValueError('Index dimension mismatch')
      if df.index.names != other.index.names:
          raise ValueError('Index mismatch')
      else:
          return
docs: Helper function to ensure that DataFrames are valid for set operations.
      Columns must be the same name in the same order, and indices must be of the
      same dimension with the same names.