text: #!/usr/bin/env python3
  
  import sys
  from calc import *
  
  _arg_number_1 = 2
  _arg_number_2 = 3
  _nb_to_test_ = 3
  
  def parsing():
      if len(sys.argv) == 2 and sys.argv[1] == "-h":
          displayChebang()
          exit(0)
      elif not(len(sys.argv) >= _arg_number_1 and len(sys.argv) <= _arg_number_2):
          exit(84)
  
      if len(sys.argv) == _arg_number_1:
          try_number(sys.argv[1])
          calc_distrib(int(sys.argv[1]))
      elif len(sys.argv) == _arg_number_2:
          try_number(sys.argv[1])
          try_number(sys.argv[2])
          calc_binom(int(sys.argv[1]), int(sys.argv[2]))
  
  def try_number(arg):
      try:
          int(arg)
      except ValueError:
          exit(84)
  
  def displayChebang():
      print ("USAGE\n"\
  "           ./203hotline [n k | d]\n\n"\
  "DESCRIPTION\n"\
  "           n    n value for the computation of (n k)\n"\
  "           k    k value for the computation of (n k)\n"\
  "           d    average duration of calls (in seconds)")
  
  def factorial(n):
      x = 1
      for i in range(2, n + 1):
          x *= i
      return x
  
  def calc_esp(actualList):
      j = 0
      E = 0
  
      for i in range(10, 60, 10):
          E += (actualList[j] * i)
          j += 1
      return E
  
  def calc_var(actualList):
      j = 0
      E1 = 0
      E2 = 0
  
      for i in range(10, 60, 10):
          E1 += (actualList[j] * (i ** 2))
          j += 1
      E2 = calc_esp(actualList) ** 2
      return E1 - E2
  