from __future__ import annotations

def get_all_children(obj, visited=None):
    if visited is None:
        visited = set()
    children = []
    children_attr = getattr(obj, "children", [])
    if "Mock" in type(children_attr).__name__ or not isinstance(children_attr, (list, tuple, set)):
        return []
    for child in children_attr:
        if child not in visited:
            visited.add(child)
            children.append(child)
            children.extend(get_all_children(child, visited))
    return list(set(children))