Raise an error message on loading pure python remappped gcode

if self.task == 1:
   if <some statement is true>:
       print('Error -> aborting G68.2')
       emccanon.CANON_ERROR( 'G68.2 ERROR: 'my error message here' )
       yield INTERP_EXIT
else:

if self.task == 0:
   if <some statement is true>:
       print('Error -> aborting G68.2')
       emccanon.CANON_ERROR( 'G68.2 ERROR: 'my error message here' )
       yield INTERP_EXIT
else:

try:
    while 1:
        if h['twp_error'] == 0:
            pass
        elif h['twp_error'] == 1:
            c.error_msg('G68.2 ERROR: TWP already active!')            
        elif h['twp_error'] == 2:
            c.error_msg('G68.2 ERROR: Cannot define TWP from active G59.2 or G59.3 offsets.')            
        elif h['twp_error'] == 3:
            c.error_msg("G68.2 ERROR: Can't enable TWP with G91 active!")
        h['twp_error'] = 0