'Returns the KKT solver selected by the user.
Removes the KKT solver from solver_opts.
Parameters
solver_opts : dict
Additional arguments for the solver.
Returns
str or None
The KKT solver chosen by the user.'

@staticmethod
def get_kktsolver_opt(solver_opts):

    if ('kktsolver' in solver_opts):
        kktsolver = solver_opts['kktsolver']
        del solver_opts['kktsolver']
    else:
        kktsolver = 'chol'
    return kktsolver
