input: Write a python function to convert a given time in hours and minutes to its corresponding phrase in words.
  assert time_in_words(3, 0) == "three o'clock"
  assert time_in_words(1, 5) == "one o'five"
  assert time_in_words(12, 30) == "twelve thirty"
  assert time_in_words(7, 14) == "seven fourteen"
  assert time_in_words(6, 45) == "six forty five"
output: def time_in_words(hours, minutes):
      num_words = ["zero", "one", "two", "three", "four", "five", "six", "seven", "eight", "nine", "ten", 
                   "eleven", "twelve", "thirteen", "fourteen", "fifteen", "sixteen", "seventeen", "eighteen", 
                   "nineteen", "twenty", "twenty one", "twenty two", "twenty three", "twenty four", 
                   "twenty five", "twenty six", "twenty seven", "twenty eight", "twenty nine", "thirty", 
                   "thirty one", "thirty two", "thirty three", "thirty four", "thirty five", "thirty six", 
                   "thirty seven", "thirty eight", "thirty nine", "forty", "forty one", "forty two", 
                   "forty three", "forty four", "forty five", "forty six", "forty seven", "forty eight", 
                   "forty nine", "fifty", "fifty one", "fifty two", "fifty three", "fifty four", "fifty five", 
                   "fifty six", "fifty seven", "fifty eight", "fifty nine"]
      
      hour_word = num_words[hours]
      minute_word = num_words[minutes]
      
      if minutes == 0:
          return f"{hour_word} o'clock"
      elif minutes < 10:
          return f"{hour_word} o'{minute_word}"
      else:
          return f"{hour_word} {minute_word}"