Splitting arguments — preserving quoted substrings — in python [closed]

def splitstring(string):
    """
    >>> string = 'apple orange "banana tree" green'
    >>> splitstring(string)
    ['apple', 'orange', 'green', '"banana tree"']
    """
    import re
    p = re.compile(r'"[w ]+"')
    quoted_item = p.search(string).group()
    newstring = p.sub('', string)
    return newstring.split() + [quoted_item]