code: def _getFuncPtrAndParams(self, funcName):
      
  
      params = None
      if isinstance(funcName, basestring):
        if funcName == 'sum':
          fp = _aggr_sum
        elif funcName == 'first':
          fp = _aggr_first
        elif funcName == 'last':
          fp = _aggr_last
        elif funcName == 'mean':
          fp = _aggr_mean
        elif funcName == 'max':
          fp = max
        elif funcName == 'min':
          fp = min
        elif funcName == 'mode':
          fp = _aggr_mode
        elif funcName.startswith('wmean:'):
          fp = _aggr_weighted_mean
          paramsName = funcName[6:]
          params = [f[0] for f in self._inputFields].index(paramsName)
      else:
        fp = funcName
  
      return (fp, params)
docs: Given the name of an aggregation function, returns the function pointer
      and param.
  
      Parameters:
      ------------------------------------------------------------------------
      funcName:  a string (name of function) or funcPtr
      retval:   (funcPtr, param)