  We describe a package realized in the Julia programming language which
performs symbolic manipulations applied to nonlinear evolution equations, their
flows, and commutators of such objects. This tool was employed to perform
contrived computations arising in the analysis of the local error of operator
splitting methods. It enabled the proof of the convergence of the basic method
and of the asymptotical correctness of a defect-based error estimator. The
performance of our package is illustrated on several examples.
