Python decorator for throttling function calls. Sleeps until it can be called

throttle.py

class throttle(object):
  """Decorator that prevents a function from being called more than once every
  time period.

  To create a function that cannot be called more than once a minute, but
  will sleep until it can be called:

    @throttle(minutes=1)
    def foo():
      pass
        
    for i in range(10):
      foo()
      print "This function has run %s times." % i
  """
  def __init__(self, seconds=0, minutes=0, hours=0):
    self.throttle_period = timedelta(
      seconds=seconds, minutes=minutes, hours=hours
    )
    self.time_of_last_call = datetime.min

  def __call__(self, fn):
    @wraps(fn)
    def wrapper(*args, **kwargs):
      now = datetime.now()
      time_since_last_call = now - self.time_of_last_call
      time_left = self.throttle_period - time_since_last_call
      if time_left > timedelta(seconds=0):
        time.sleep(time_left.seconds)
      self.time_of_last_call = datetime.now()
      return fn(*args, **kwargs)

    return wrapper

Isn't this missing:

import time
from datetime import datetime, timedelta
from functools import wraps

in line #29 it should probably be time.sleep(time_left.total_seconds())