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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _detect_circle(nodes=None, dependencies=None, traveled=None, path=None):
 """ Recursively iterate over nodes checking if we've traveled to that node before. """

    # Verify nodes and traveled types
    if nodes is None:
        nodes = {}
    elif not isinstance(nodes, dict):
        raise TypeError('"nodes" must be a dictionary')
    if dependencies is None:
        return
    elif not isinstance(dependencies, set):
        raise TypeError('"dependencies" must be a set')
    if traveled is None:
        traveled = []
    elif not isinstance(traveled, list):
        raise TypeError('"traveled" must be a list')
    if path is None:
        path = []

    if not dependencies:
        # We're at the end of a dependency path.
        return []

    # Recursively iterate over nodes,
    # and gather dependency children nodes.
    children = []
    for name in dependencies:
        # Path is used for circular dependency exceptions
        # to display to the user the circular path.
        new_path = list(path)
        new_path.append(name)

        # Check if we've traveled to this node before.
        if name in traveled:
            raise CircularDependencyException(new_path)

        # Make recursive call
        node_children = _detect_circle(nodes=nodes,
                                       dependencies=nodes[name],
                                       traveled=traveled + list(name),
                                       path=new_path)

        # Create node for this dependency with children.
        node = DependencyNode(name)
        for child in node_children:
            child.parent = node
            node.add_child(child)
        children.append(node)

    return children