@staticmethod
def _edge(node1: str, node2: str, attribute: str):
    """
        Creates an edge to link nodes.

        :param node1: The first node.
        :param node2: The second node.
        :param attribute: The attributes.
        :return: A string to represents the edge.
        """
    return '"{0}" -> "{1}" [{2}]\n'.format(node1, node2, attribute)
