Parse method should take in nullable function

[smilecs]

Is your feature request related to a problem? Please describe.
Currently, the parse method in the LiveDataHandler method takes in a non-nullable function parameter, this should be edited to take in a nullable function.

Describe the solution you'd like
The parse method should be able to take in a non-nullable function or it should have a default empty function.

Describe alternatives you've considered
N/A

Additional context
N/A