<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def branch(self):
 """ Get a flattened representation of the branch. @return: A flat list of nodes. @rtype: [L{Element},..] """

        branch = [self]
        for c in self.children:
            branch += c.branch()
        return branch