def _create_graph(structure_dict):
    """Creates pydot graph from the pipeline structure dict.

    Args:
        structure_dict (dict): dict returned by step.upstream_structure

    Returns:
        graph (pydot.Dot): object representing upstream pipeline structure (with regard to the current Step).
    """
    graph = pydot.Dot()
    for node in structure_dict['nodes']:
        graph.add_node(pydot.Node(node))
    for node1, node2 in structure_dict['edges']:
        graph.add_edge(pydot.Edge(node1, node2))
    return graph