I have a class definition here:

```
class Graph:
    def __init__(self,directional = False,simple=True,Filename=None):
        self.adjacencyList = {}
        self.directional = directional
        self.simple = simple

```

and I designed `__str__` method for it like this:

```
def __str__(self):
    simple = "Simple: "+ str(self.simple)+"\n"
    directional = "Directional: " + str(self.directional)+"\n"
    items = "{\n"
    for vertex in self.adjacencyList.keys():
        items = items +"\t"+str(vertex)+str(self.adjacencyList[vertex])+"\n"
    items += "}"
    string = simple + directional + items
    return string

```

I found it is so verbose and I am thinking maybe there is some cleaner way to do it using fewer lines of code.

Can you give me some suggestions?