from typing import Mapping
from typing import Sequence


def get_sample_graph() -> Mapping[str, Sequence[str]]:
    """
    Args:
        None

    Returns:
        graph: Python dictionary representing an adjacency list
    """
    graph = {
        "1": ["2", "3", "4"],
        "2": ["5", "6"],
        "5": ["9", "10"],
        "4": ["7", "8"],
        "7": ["11", "12"],
    }
    return graph