def METHOD_NAME(graph):
    """Inverts a dependant's graph to yield a dependency graph.
    Notes
    -----
    The graph must be directed and acyclic.
    Parameters
    ----------
    graph: dict(str, list(str))
        The graph to invert. Each key in the dictionary represents a node in the graph, and each
        string in the value list represents a node which depends on the node defined by the key.
    Returns
    -------
    dict(str, list(str))
        The inverted graph. Each key in the dictionary represents a node in the graph, and each
        string in the value list represents a node which the node defined by the key depends on.
    """
    dependencies = {}
    for node in graph:
        if node not in dependencies:
            dependencies[node] = []
        for dependant in graph[node]:
            if dependant not in dependencies:
                dependencies[dependant] = []
            if node not in dependencies[dependant]:
                dependencies[dependant].append(node)
    return dependencies