getsource not get correct source code

```
import dill


class A:
    def a(self):
        print("a")


print(dill.source.getsource(A))


class A:
    def b(self):
        print("b")


print(dill.source.getsource(A))
```
Which will return
```
class A:
    def b(self):
        print("b")

class A:
    def b(self):
        print("b")
```