print system memory usage Linux/Ubuntu Python

print_memory_usage.py

def print_memory_usage():
    import os
    lines = os.popen('free -t -m').readlines()
    tot_m, used_m, free_m = map(int, lines[-1].split()[1:])
    for l in lines:
        print(l.rstrip())

    return {'total_memory': tot_m, 'used_memory': used_m, 'free_memory': free_m}