def f(): items = [1, 2, 3, 4] result = [] for i in items: result.append(i) # PERF402 def f(): items = [1, 2, 3, 4] result = [] for i in items: result.insert(0, i) # PERF402 def f(): items = [1, 2, 3, 4] result = [] for i in items: result.append(i * i) # OK def f(): items = [1, 2, 3, 4] result = {} for i in items: result[i].append(i * i) # OK class Foo: def append(self, x): pass def f(): items = [1, 2, 3, 4] result = Foo() for i in items: result.append(i) # OK def f(): import sys for path in ("foo", "bar"): sys.path.append(path) # OK def f(): items = [1, 2, 3, 4] result = [] async for i in items: result.append(i) # PERF402