Given this nest dictionary grab the word "hello".

Notes:

• We have provided a dic object.
• Iterate over it and return last index word for target which is hello.

Instructions:

• Program should be written in file build.py

• Function name should be solution.

• Input

   Type:  Dictionary
   Value: {'a1': [4, 2, 7, ("hello")]}
  

• Expected Output

    Type:  String
    Value: ("hello")