<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def follow(self, chars):
 """ Traverse the GADDAG to the node at the end of the given characters. Args: chars: An string of characters to traverse in the GADDAG. Returns: The Node which is found by traversing the tree. """

        chars = chars.lower()

        node = self.node
        for char in chars:
            node = cgaddag.gdg_follow_edge(self.gdg, node, char.encode("ascii"))
            if not node:
                raise KeyError(char)

        return Node(self.gdg, node)