Quebuster busting my mind

# M36 shift NEUTRAL
REMAP=M36   prolog=gear_change_prolog python=m36_remap epilog=gear_change_epilog modalgroup=10

def gear_change_prolog(self, **words):
    print"gear change prolog"
    return INTERP_OK
    
def gear_change_epilog(self, **words):
    print "gear change epilog"
    #lsw1_status = emccanon.GET_EXTERNAL_DIGITAL_INPUT(0,0)
    #print "limit switch 1 status =" , lsw1_status
    return INTERP_OK

def m36_remap(self,**words):
    try:
        spindle_run_inhibit(self)   
        hyd_shift_neutral(self)
        yield INTERP_EXECUTE_FINISH        
        #lsw1_status = emccanon.GET_EXTERNAL_DIGITAL_INPUT(0,0)
        #print "limit switch 1 status =" , lsw1_status          
        print "end of M36 remap"
        #return INTERP_OK
                                
    except IOError as e:
        print "I/O error({0}): {1}".format(e.errno, e.strerror)
        #return ReturnERROR()  
def in_case_of_spindle_running(self):
    print "stopping spindle"
    self.execute("M5")
    
def zero_speed_detect(self):
    # we need to check the value of the hal pin spindle.0.at-speed
    # the spindle.0.at-speed pin must be connected to digital input 16
    # wait 5 seconds for the spindle to wind down
    self.execute("M66 P16 L3 Q5")
    # check the zero speed digital input 
    pin_status = emccanon.GET_EXTERNAL_DIGITAL_INPUT(16,0)
    print "zero speed detect =" , pin_status
    if pin_status == 1:
        return INTERP_OK
    else:
        #enter a message in the error log and return an error
        self.set_errormsg("something went wrong, spindle still running")
        return INTERP_ERROR

def spindle_run_inhibit(self):
    print "checking if spindle is running"
    try:
        spindle_status = self.params["_spindle_on"]
        print "M3/M4 ACTIVE" , spindle_status
        if spindle_status == 1:
            in_case_of_spindle_running(self)
            zero_speed_detect(self)
                    
        if spindle_status == 0:
            # potientally the spindle could be off but still rotating so we need to check
            zero_speed_detect(self)
        
        # the spindle is now off and zero speed has been detected
        # ok to switch gears    
        #return INTERP_OK
        
    except Exception, e:
        return "%s" % e