code: def fail_unknown_dialect(compiler: "SQLCompiler", task: str) -> None:
      
      raise NotImplementedError(
          "Don't know how to {task} on dialect {dialect!r}. "
          "(Check also: if you printed the SQL before it was bound to an "
          "engine, you will be trying to use a dialect like StrSQLCompiler, "
          "which could be a reason for failure.)".format(
              task=task,
              dialect=compiler.dialect
          )
      )
docs: Raise :exc:`NotImplementedError` in relation to a dialect for which a
      function hasn't been implemented (with a helpful error message).