Cannot use Master Key with a logged in user

[cjbland]

I'm developing a very basic administrator portal that needs to update objects that do not belong to them. Because I have a logged in user, the execute method is taking the session token over the Master Key:

ParsePy/parse_rest/connection.py

Lines 132 to 135 in 1623d6d

	if ACCESS_KEYS.get('session_token'):
	request.add_header('X-Parse-Session-Token', ACCESS_KEYS.get('session_token'))
	elif master_key:
	request.add_header('X-Parse-Master-Key', master_key)

Could this be broken into two ifs instead of an if/elif?