## Overview of the feature The following mod file is valid in NOCMODL: ```plaintext NEURON { SUFFIX test } BREAKPOINT { SOLVE states } STATE { n } INITIAL { n = 1 } DERIVATIVE states { n' = -n } ``` Unfortunately, NMODL does not work: ```plaintext [NMODL] [error] :: SympySolverVisitor :: Solve method not supported [NMODL] [error] :: NeuronSolveVisitor :: solver method '' not supported ``` NOCMODL actually implicitly converts the `SOLVE states` statement into `SOLVE states METHOD derivimplicit`. NMODL should match this behavior.