4. Complete the function number_okay which takes a string as input and returns True if the string is the name of one of the numbers 1...5 (i.e. "one", "two", "three", "four", "five"), and False otherwise. You can assume that the string given to number_okay is all lowercase letters.

def number_okay(num_string):

 # write your code here

print(number_okay("three"))

print(number_okay("eleven"))