<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def etree_to_string(root, pretty_print=True, xml_declaration=True, encoding='utf-8'):
 """Dump XML etree as a string."""

    return etree.tostring(
        root,
        pretty_print=pretty_print,
        xml_declaration=xml_declaration,
        encoding=encoding,
    ).decode('utf-8')