<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def from_file(cls, jss, filename):
 """Create a new JSSObject from an external XML file. Args: jss: A JSS object. filename: String path to an XML file. """

        tree = ElementTree.parse(filename)
        root = tree.getroot()
        return cls(jss, root)