code: def _parse_radfunc(self, func_name):
          
          node = self.root.find(func_name)
          grid = node.attrib["grid"]
          values = np.array([float(s) for s in node.text.split()])
  
          return self.rad_grids[grid], values, node.attrib
docs: Parse the first occurence of func_name in the XML file.