Can't threads be executed in the remapping script?

#!/usr/bin/env python3

import struct
import sys 
import os
from interpreter import *
import hal
import linuxcnc
import _thread



def Z_jogs(self,a):
        print('a = ',a)
        b=a
        print('b=',b)
        while True :
            x = hal.get_value('lcec.0.5.RXPDO-5') #read EtherCAT io  
            print('x_in5 =',x)
            if x == 1:
                print("in5 = ",x)
                self.execute("G0 Z %d"%b)    #Control Z axis movement
                b += a
            elif x == 0:
                print("in5 = ",x)
            if hal.get_value('lcec.0.5.TXPDO-2') == 1:   
                break 

# read EtherCAT io 
def m203(self,**words):
    yield INTERP_EXECUTE_FINISH
    if self.task:
        self.Z_jogs = Z_jogs()
        a = (words['s'])
        print("a=",a)
        try:
           _thread.start_new_thread(Z_jogs,(a,))
           print('qw')
        except:
           print('erro')