Determines if a given string is a valid D-Bus object path.
You should ensure that a string is a valid D-Bus object path before passing it to Variant.object_path.
A valid object path starts with `/` followed by zero or more sequences of characters separated by `/` characters. Each sequence must contain only the characters `A-Z[0-9]_`. No sequence (including the one following the final `/` character) may be empty.
a normal C nul-terminated string