code: def _evaluateplanarRforces(Pot,R,phi=None,t=0.):
      
      from .Potential import _isNonAxi
      isList= isinstance(Pot,list)
      nonAxi= _isNonAxi(Pot)
      if nonAxi and phi is None:
          raise PotentialError("The (list of) planarPotential instances is non-axisymmetric, but you did not provide phi")
      if isinstance(Pot,list) \
              and nu.all([isinstance(p,planarPotential) for p in Pot]):
          sum= 0.
          for pot in Pot:
              if nonAxi:
                  sum+= pot._Rforce_nodecorator(R,phi=phi,t=t)
              else:
                  sum+= pot._Rforce_nodecorator(R,t=t)
          return sum
      elif isinstance(Pot,planarPotential):
          if nonAxi:
              return Pot._Rforce_nodecorator(R,phi=phi,t=t)
          else:
              return Pot._Rforce_nodecorator(R,t=t)
      else: #pragma: no cover 
          raise PotentialError("Input to 'evaluatePotentials' is neither a Potential-instance or a list of such instances")
docs: Raw, undecorated function for internal use