code: def get_integrator(integrator):
      
      integrator_types = set(['trapz', 'cumtrapz', 'simps', 'romb'])
      integrator_funcs = [integrate.trapz, integrate.cumtrapz, integrate.simps, integrate.romb]
  
      if isinstance(integrator, int) and 0 <= integrator < len(integrator_types):
          integrator = integrator_types[integrator]
      if isinstance(integrator, basestring) and integrator in integrator_types:
          return getattr(integrate, integrator)
      elif integrator in integrator_funcs:
          return integrator
      else:
          print('Unsupported integration rule: {0}'.format(integrator))
          print('Expecting one of these sample-based integration rules: %s' % (str(list(integrator_types))))
          raise AttributeError
      return integrator
docs: Return the scipy.integrator indicated by an index, name, or integrator_function
  
      >> get_integrator(0)