input: Write a python function to add global edges to a pygraphviz AGraph object based on a dictionary input.
  assert add_global_edges(F, {"A": {"B": {}}}) == None
  assert add_global_edges(F, {"X": {"Y": {"style": "dashed"}}}) == None
  assert add_global_edges(F, {"Node1": {"Node2": {"color": "red"}}}) == None
output: def add_global_edges(agraph, edges_dict):
      for src, targets in edges_dict.items():
          for dst, attrs in targets.items():
              agraph.add_edge(src, dst, **attrs)