An object of class causal_model. It essentially returns a
list containing the elements comprising a model
(e.g. 'statement', 'nodal_types' and 'DAG') with the parameter matrix
attached to it.
Arguments
model
A causal_model. A model object generated by
make_model.
P
A data.frame. Parameter matrix. Not required but may be
provided to avoid repeated computation for simulations.