code: def validate_key(self, key):
          
          if not models.PasswordResetToken.valid_tokens.filter(key=key).exists():
              raise serializers.ValidationError(
                  _("The provided reset token does not exist, or is expired.")
              )
  
          return key
docs: Validate the provided reset key.
  
          Returns:
              The validated key.
  
          Raises:
              serializers.ValidationError:
                  If the provided key does not exist.