#
#  Does the provided password meet the requirements of at least 7 characters,
#  at least one uppercase letter, at least one lowercase letter, and at least
#  one digit.
#
#  Parameters:
#    password: The password to evaluate
#
#  Returns:
#    True if the password meets all of the requirements.  False otherwise.
#
def passwordOK(password):
  # Check the length requirement
  if len(password) < 7:
    return False

  # Check that the password has an uppercase letter
  if password == password.lower():
    return False

  # Check that the password has a lowercase letter in it
  has_lower = False
  for ch in "abcdefghijklmnopqrstuvwxyz":   # for each lowercase letter
    if password.find(ch) >= 0:      # if the current letter is in the password
      has_lower = True

  if has_lower == False:
    return False

  # Check that the password has a digit in it
  has_digit = False
  for ch in password:                      # for each character in the password
    if ch >= "0" and ch <= "9":
      has_digit = True

  return has_digit
      
def main():
  password = input("Enter a password to check: ")
  if passwordOK(password):
    print("That password meets all the requirements.")
  else:
    print("You can't use that password.  You'll have to choose a different one.")

main()