Flatten a list

gistfile1.py

def flatten(list_):
    nested = True
    while nested:
        iter_ = False
        temp = []
        for element in list_:
            if isinstance(element, list):
                temp.extend(element)
                iter_ = True
            else:
                temp.append(element)
        nested = iter_
        list_ = temp[:]
    return list_

# Example:
# flatten(["test", ["test1", "test2", ["test", "test1"], "test3"], "test4"]   -> ["test", "test1", "test2", "test", "test1", "test3", "test4"]