def validate_key(self, key):
if not models.PasswordResetToken.valid_tokens.filter(key=key).exists():<EOL><INDENT>raise serializers.ValidationError(<EOL>_("<STR_LIT>")<EOL>)<EOL><DEDENT>return key<EOL>
Validate the provided reset key.

Returns:
    The validated key.

Raises:
    serializers.ValidationError:
        If the provided key does not exist.