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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 strip_v2_elements(etree_obj):
 """In-place remove elements and attributes that are only valid in v2 types. Args: etree_obj: ElementTree ElementTree holding one of the DataONE API types that changed between v1 and v2. """

    if etree_obj.tag == v2_0_tag('logEntry'):
        strip_logEntry(etree_obj)
    elif etree_obj.tag == v2_0_tag('log'):
        strip_log(etree_obj)
    elif etree_obj.tag == v2_0_tag('node'):
        strip_node(etree_obj)
    elif etree_obj.tag == v2_0_tag('nodeList'):
        strip_node_list(etree_obj)
    elif etree_obj.tag == v2_0_tag('systemMetadata'):
        strip_system_metadata(etree_obj)
    else:
        raise ValueError('Unknown root element. tag="{}"'.format(etree_obj.tag))