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': ['add_blank_lines_for_python_control_statements']} 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 Given python(A file with a main block): import os def main(): print('hello') if __name__ == '__main__': main() Execute(Fix the file): let g:ale_fixers = {'python': ['add_blank_lines_for_python_control_statements']} ALEFix Expect python(extra newlines shouldn't be added to the main block): import os def main(): print('hello') if __name__ == '__main__': main()