#!/usr/bin/env python3

from time import sleep

def tail (filename, printed_lines_count=0, polling_interval_duration=0.01):
  line_count = sum(1 for line in open(FILENAME))
  f = open(FILENAME,'r')
  cpt = 0
  while cpt < line_count - printed_lines_count :
    cpt += 1
    next(f)

  try:
    while True:
      try:
        line_read = next(f)
        print(filename,":",line_read[:-1])
      except:
        sleep(polling_interval_duration)
  except:
    f.close()