old_contents: # actual code
  def leap_year(year: int) -> bool:
      """
      Calculate if it is a leap year or not.
      A leap year is defined as one that
      - is divisible by 4,
      - but is not otherwise divisible by 100
      - unless it is also divisible by 400.
  
      :param year: the year
      :return: True if year is a leap year, False else
  
      >>> leap_year(1)
      False
      """
      pass
  
  
  # py-test
  def test_leap_year():
      assert not leap_year(1)
  
new_contents: # actual code
  def leap_year(year: int) -> bool:
      """
      Calculate if it is a leap year or not.
      A leap year is defined as one that
      - is divisible by 4,
      - but is not otherwise divisible by 100
      - unless it is also divisible by 400.
  
      :param year: the year
      :return: True if year is a leap year, False else
  
      >>> leap_year(1)
      False
      """
      pass
  
  
  # py-test
  def test_leap_year():
      assert leap_year(1) is False
  
subject: fix for new PyCharm