code: def main(guess_a=1., guess_b=0., power=3, savetxt='None', verbose=False):
      
      x, sol = solve(guess_a, guess_b, power)  # see function definition above
      assert sol.success
      if savetxt != 'None':
          np.savetxt(x, savetxt)
      else:
          if verbose:
              print(sol)
          else:
              print(x)
docs: Example demonstrating how to solve a system of non-linear equations defined as SymPy expressions.
  
      The example shows how a non-linear problem can be given a command-line interface which may be
      preferred by end-users who are not familiar with Python.