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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 etree_replace_namespace(etree_obj, ns_str):
 """In-place change the namespace of elements in an ElementTree. Args: etree_obj: ElementTree ns_str : str The namespace to set. E.g.: ``http://ns.dataone.org/service/types/v1``. """


    def _replace_recursive(el, n):
        el.tag = re.sub(r'{.*\}', '{{{}}}'.format(n), el.tag)
        el.text = el.text.strip() if el.text else None
        el.tail = el.tail.strip() if el.tail else None
        for child_el in el:
            _replace_recursive(child_el, n)

    _replace_recursive(etree_obj, ns_str)