Meaning of "test_data: n_test" in python 3.8
This is a if statement in python, it checks if test_data exists and if exists then sets the value of the variable n_data to the string length of test_data variable.
I am following a tutorial on Neural_Networks and it uses python2.7 and the line of code I am confused with is the if statement  '''
if test_data: n_test = len(test_data)
''' and I ever came across this syntax in python 3.8 and please explain me what does test_data: n_test means. Thank You