



"""simple docstring"""
def 			_SCREAMING_SNAKE_CASE						(__lowerCAmelCase							) ->						bool:







  '''simple docstring'''


  return credit_card_number.startswith(("""34""", """35""", """37""", """4""", """5""", """6""")							)


def 			_SCREAMING_SNAKE_CASE						(__lowerCAmelCase							) ->						bool:







  '''simple docstring'''


  lowercase_								= credit_card_number
  lowercase_								= 0
  lowercase_								= len(__lowerCAmelCase							) - 2
  for i in range(__lowerCAmelCase ,  -1 ,  -2							):
    #  double the value of every second digit
    lowercase_								= int(cc_number[i]							)
    digit *= 2
    # If doubling of a number results in a two digit number
    # i.e greater than 9(e.g., 6 × 2 = 12),
    # then add the digits of the product (e.g., 12: 1 + 2 = 3, 15: 1 + 5 = 6),
    # to get a single digit number.
    if digit > 9:
      digit %= 10
      digit += 1
    lowercase_								= cc_number[:i] + str(__lowerCAmelCase							) + cc_number[i + 1 :]
    total += digit

  # Sum up the remaining digits
  for i in range(len(__lowerCAmelCase							) - 1 ,  -1 ,  -2							):
    total += int(cc_number[i]							)

  return total % 10 == 0


def 			_SCREAMING_SNAKE_CASE						(__lowerCAmelCase							) ->						bool:







  '''simple docstring'''


  lowercase_								= F'''{credit_card_number} is an invalid credit card number because'''
  if not credit_card_number.isdigit():
    print(F'''{error_message} it has nonnumerical characters.'''							)
    return False

  if not 13 <= len(__lowerCAmelCase							) <= 16:
    print(F'''{error_message} of its length.'''							)
    return False

  if not validate_initial_digits(__lowerCAmelCase							):
    print(F'''{error_message} of its first two digits.'''							)
    return False

  if not luhn_validation(__lowerCAmelCase							):
    print(F'''{error_message} it fails the Luhn check.'''							)
    return False

  print(F'''{credit_card_number} is a valid credit card number.'''							)
  return True


if __name__ == "__main__":
       import doctest

       doctest.testmod()
       validate_credit_card_number("4111111111111111")
       validate_credit_card_number("32323")






"""simple docstring"""
from __future__ import annotations

import math
from collections import Counter
from string import ascii_lowercase


def 			_SCREAMING_SNAKE_CASE						(__lowerCAmelCase							) ->						None:







  '''simple docstring'''


  lowercase_					,    lowercase_								= analyze_text(__lowerCAmelCase							)
  lowercase_								= list(""" """ + ascii_lowercase							)
  # what is our total sum of probabilities.
  lowercase_								= sum(single_char_strings.values()							)

  # one length string
  lowercase_								= 0
  # for each alpha we go in our dict and if it is in it we calculate entropy
  for ch in my_alphas:
    if ch in single_char_strings:
      lowercase_								= single_char_strings[ch]
      lowercase_								= my_str / all_sum
      my_fir_sum += prob * math.loga(__lowerCAmelCase							)  # entropy formula.

    # print entropy
  print(F'''{round(-1 * my_fir_sum							):.1f}'''							)

  # two len string
  lowercase_								= sum(two_char_strings.values()							)
  lowercase_								= 0
  # for each alpha (two in size) calculate entropy.
  for cha in my_alphas:
    for cha in my_alphas:
      lowercase_								= cha + cha
      if sequence in two_char_strings:
        lowercase_								= two_char_strings[sequence]
        lowercase_								= int(__lowerCAmelCase							) / all_sum
        my_sec_sum += prob * math.loga(__lowerCAmelCase							)

    # print second entropy
  print(F'''{round(-1 * my_sec_sum							):.1f}'''							)

  # print the difference between them
  print(F'''{round((-1 * my_sec_sum) - (-1 * my_fir_sum)							):.1f}'''							)


def 			_SCREAMING_SNAKE_CASE						(__lowerCAmelCase							) ->						tuple[dict, dict]:







  '''simple docstring'''


  lowercase_								= Counter()  # type: ignore
  lowercase_								= Counter()  # type: ignore
  single_char_strings[text[-1]] += 1

  # first case when we have space at start.
  two_char_strings[" " + text[0]] += 1
  for i in range(0 ,  len(__lowerCAmelCase							) - 1							):
    single_char_strings[text[i]] += 1
    two_char_strings[text[i : i + 2]] += 1
  return single_char_strings, two_char_strings


def 			_SCREAMING_SNAKE_CASE						() ->						str:







  '''simple docstring'''


  import doctest

  doctest.testmod()
  # text = (
  #     "Had repulsive dashwoods suspicion sincerity but advantage now him. Remark "
  #     "easily garret nor nay. Civil those mrs enjoy shy fat merry. You greatest "
  #     "jointure saw horrible. He private he on be imagine suppose. Fertile "
  #     "beloved evident through no service elderly is. Blind there if every no so "
  #     "at. Own neglected you preferred way sincerity delivered his attempted. To "
  #     "of message cottage windows do besides against uncivil.  Delightful "
  #     "unreserved impossible few estimating men favourable see entreaties. She "
  #     "propriety immediate was improving. He or entrance humoured likewise "
  #     "moderate. Much nor game son say feel. Fat make met can must form into "
  #     "gate. Me we offending prevailed discovery. "
  # )

  # calculate_prob(text)


if __name__ == "__main__":
       main()

