new_contents: import unittest, difflib, texttable
  
  class AssertSQLMixin(object):
      """
      Mixin for assertSqlResults
      """
      def assertSqlResults(conn, sql, *rows):
          header, rows = rows[0], rows[1:]
          results = fetch_result_rows(conn, sql)
  
          expected = tableize_grid(header, rows)
          actual   = tableize_obj_list(header, results)
  
          diff = difflib.unified_diff(expected, actual)
          if diff:
              raise AssertionError("Assert failed for sql\n{sql}\n\n{diff}".format(
                  sql = sql,
                  diff = diff,
              ))
  
subject: Add AssertSQLMixin