import random


def run_single_walk(start_node, graph, length):
    """Run a single random walk on a graph from a given start node.

    Parameters
    ----------
    graph : networks.MultiGraph
        The graph on which the random walk is to be run.
    start_node : str
        The identifier of the node from which the random walk starts.
    length : int
        The length of the random walk.

    Returns
    -------
    list of str
        A path of the given length, with each element corresponding to a node
        along the path.
    """
    path = [start_node]
    for i in range(1, length):
        start_node = random.choice(list(graph[start_node]))
        path.append(start_node)
    return path