NameError: name 'BayesianNetwork' is not defined

The error message "NameError: name 'BayesianNetwork' is not defined" means that the name "BayesianNetwork" is not recognized or defined in the current scope. This can happen if you have not imported the module that defines the BayesianNetwork class.

To fix this error, make sure you have imported the module that defines the BayesianNetwork class. For example, if you are using the `pgmpy` library to work with Bayesian networks, you can import the BayesianNetwork class as follows:

from pgmpy.models import BayesianNetwork

# Now you can use BayesianNetwork class in your code

If you have already imported the module and are still getting this error, make sure that the spelling and capitalization of the class name match the definition in the module.