Bug in hc_mopac example

[emarinri]

• MolSSI Workflow version:
• Python version:
• Operating System: MacOS Mojave 10.14.6

Description

Bug found when closing a step in Seamm using the (X) button

What I Did

1. Open HC_mopac example
2. Click on custom step
3. Click on close button (the X red button)
4. Get an error

Error: 1
RuntimeError Exception in Tk callback
  Function: <bound method MegaToplevel._userdeletewindow of <_Pmw.Pmw_2_0_1.lib.PmwDialog.Dialog object at 0x11d6dae48>> (type: <class 'method'>)
  Args: ()
Traceback (innermost last):
  File "/Users/meliseo/miniconda3/envs/seamm-dev/lib/python3.7/site-packages/Pmw/Pmw_2_0_1/lib/PmwBase.py", line 1776, in __call__
    return self.func(*args)
  File "/Users/meliseo/miniconda3/envs/seamm-dev/lib/python3.7/site-packages/Pmw/Pmw_2_0_1/lib/PmwBase.py", line 1045, in _userdeletewindow
    self._usermodaldeletefunc()
  File "/Users/meliseo/miniconda3/envs/seamm-dev/lib/python3.7/site-packages/Pmw/Pmw_2_0_1/lib/PmwDialog.py", line 132, in _doCommand
    return command(name)
  File "/Users/meliseo/miniconda3/envs/seamm-dev/lib/python3.7/site-packages/custom_step/tk_custom.py", line 118, in handle_dialog
    "Don't recognize dialog result '{}'".format(result)
RuntimeError: Don't recognize dialog result 'None'