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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def get_pyquery(self, tree=None, page_numbers=None):

 """
 Wrap given tree in pyquery and return.
 If no tree supplied, will generate one from given page_numbers, or
 all page numbers.
 """

        if not page_numbers:
            page_numbers = []
        if tree is None:
            if not page_numbers and self.tree is not None:
                tree = self.tree
            else:
                tree = self.get_tree(page_numbers)
        if hasattr(tree, 'getroot'):
            tree = tree.getroot()
        return PyQuery(tree, css_translator=PDFQueryTranslator())