Python considers empty strings as having boolean value of "false" and non-empty strings as having boolean value of "true".
So there're only two possible outcomes of the expression, i.e. for empty string and for non-empty string.
Second thing to notice is that which value of "or" and "and" operator are returned. Python does not return just true or false value, for strings and or/and operator it returns one of the strings (considering they have value of true or false). Python uses lazy approach:
For "and" operator if left value is true, then right value is checked and returned. if left value is false, then it is returned
For "or" operator if first value is true, then it is returned. otherwise if second value is false, then second value is returned
parameter = 'test'
print( parameter and (" " + parameter) or "" )
ouput: test
parameter = ''
print( parameter and (" " + parameter) or "" )
output:(empty string)
