Before:
  Save g:ale_fixers

After:
  Restore

Given python(Some Python without blank lines):
  def foo():
      return 1


  def bar():
      return 1
      return 4


  def bar():
      if x:
          pass
          for l in x:
              pass
          for l in x:
              pass
              break
              continue
      elif x:
          pass
          while x:
              pass
          while x:
              pass
      else:
          pass
      if x:
          pass
      elif x:
          pass
      else:
          pass

Execute(Blank lines should be added appropriately):
  let g:ale_fixers = {'python': ['ale#handlers#python#AddLinesBeforeControlStatements']}
  ALEFix

Expect python(Newlines should be added):
  def foo():
      return 1


  def bar():
      return 1

      return 4


  def bar():
      if x:
          pass

          for l in x:
              pass

          for l in x:
              pass

              break

              continue
      elif x:
          pass

          while x:
              pass

          while x:
              pass
      else:
          pass

      if x:
          pass
      elif x:
          pass
      else:
          pass