def _traverse(self, node: PrefixTreeNode, prefix: str,
visit: Callable) -> None:
"""Traverse this prefix tree with recursive depth-first traversal.
Start at the given node with the given prefix representing its path in
this prefix tree and visit each node with the given visit function."""
# Once the node is filled with characters and contains a terminal node, it'll append
if node.is_terminal():
visit(prefix)
for char in node.children.keys():
next_node = node.get_child(char)
self._traverse(next_node, prefix + char, visit)
def test_init_and_properties(self):
character = 'a'
node = PrefixTreeNode(character)
# Verify node character
assert isinstance(node.character, str)
print(node.character)
assert node.character == 'a'
# Verify children nodes structure
assert isinstance(node.children, PrefixTreeNode.CHILDREN_TYPE)
assert len(node.children) == 26
assert node.children == [None] * 26
assert node.num_children() == 0
# Verify terminal boolean
assert node.terminal is False
assert node.is_terminal() is False
