how to know runtime of a function in python code example

Example 1: how to record execution time in python

import time

start = time.time()
print("hello")
end = time.time()
print(end - start)

Example 2: python how to measure code run in time

import time
start_time = time.time()
main()
print("--- %s seconds ---" % (time.time() - start_time))