ECHO007 - empty line inside method


why:

  an empty line inside a method separates “parts,” which means the
  method does more than one thing. decompose with new methods instead.
  see https://www.yegor256.com/2014/11/03/empty-line-code-smell.html


bad:

  def save(user):
      user.validate()

      user.persist()


good:

  def save(user):
      user.validate()
      user.persist()


configure in pyproject.toml:

  [tool.echo-python.echo007]
  exclude_tests = false


`exclude_tests` defaults to true and skips functions whose names
start with `test_`.
