human
Complete the below
def getUrls(sheet):

    ''''Retrieve all ``url(urlstring)`` values (in e.g.
    :class:`cssutils.css.CSSImportRule` or :class:`cssutils.css.CSSValue`
    objects of given `sheet`.
    :param sheet:
    :class:`cssutils.css.CSSStyleSheet` object whose URLs are yielded
    This function is a generator. The generated URL values exclude ``url(`` and
    ``)`` and surrounding single or double quotes.'
    '''
assistant
#Here is the Python code you requested.
    for importrule in (r for r in sheet if (r.type == r.IMPORT_RULE)):
        (yield importrule.href)
    def styleDeclarations(base):
        'recursive    generator    to    find    all    CSSStyleDeclarations'
        if hasattr(base, 'cssRules'):
            for rule in base.cssRules:
                for s in styleDeclarations(rule):
                    (yield s)
        elif hasattr(base, 'style'):
            (yield base.style)
    for style in styleDeclarations(sheet):
        for p in style.getProperties(all=True):
            for v in p.propertyValue:
                if (v.type == 'URI'):
                    (yield v.uri)