docstr: Return a tuple of parameters to the function.
          
code: def get_parameters(self):
      """Return a tuple of parameters to the function."""
      if self.__params is None:
          self.__params = self.__idents_matching(
              lambda x: x & DEF_PARAM
          )
      return self.__params
  
imports: import _symtable
  from _symtable import USE, DEF_GLOBAL, DEF_NONLOCAL, DEF_LOCAL, DEF_PARAM, DEF_IMPORT, DEF_BOUND, DEF_ANNOT, SCOPE_OFF, SCOPE_MASK, FREE, LOCAL, GLOBAL_IMPLICIT, GLOBAL_EXPLICIT, CELL
  import weakref
label_desc: Use image node_id 2 for calling the Function obj's underlying member method code with example usage: obj.get_parameters() and returns: self