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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 valid_as_v2_0(voevent):
 """Tests if a voevent conforms to the schema. Args: voevent(:class:`Voevent`):
 Root node of a VOEvent etree. Returns: bool: Whether VOEvent is valid """

    _return_to_standard_xml(voevent)
    valid_bool = voevent_v2_0_schema.validate(voevent)
    _remove_root_tag_prefix(voevent)
    return valid_bool