Dirty fix for error '_object_has_no_attribute_'getSlave' in EtherCAT extension

traceback:
File "/home/developer/WorkData/PLC/beremiz/beremiz/IDEFrame.py", line 1433, in OnPouSelectedChanged
window.RefreshView()
File "/home/developer/WorkData/PLC/beremiz/beremiz/etherlab/ConfigEditor.py", line 837, in RefreshView
self.RefreshProcessVariables()
File "/home/developer/WorkData/PLC/beremiz/beremiz/etherlab/ConfigEditor.py", line 886, in RefreshProcessVariables
slaves = self.Controler.GetSlaves(**self.CurrentNodesFilter)
File "/home/developer/WorkData/PLC/beremiz/beremiz/etherlab/EthercatMaster.py", line 341, in GetSlaves
for slave in self.Config.getConfig().getSlave():
<type 'exceptions.AttributeError'>:_'lxml.etree._Element'_object_has_no_attribute_'getSlave'

Steps to reproduce problem:

- Add new EtherCAT master
- Add new EthercatNode to the master
- double click on


this is looks like dirty hack to fix strange problem with initial[0]
changing its type after returning from _init_ method to lxml.etree._Element
As a result all methods generated by class factory are lost.

For example, in function initMethod initial[0].__class__ points to
xmlclass.xmlclass.Config. After map(self.append, initial)
self.Config.__class__ is 'xmlclass.xmlclass.Config' as well.
But after returning from initMethod (_init) in CreateElement
self.Config.__class__ has changed to lxml.etree._Element.


I've noticed similar behavior if copy/deepcopy is used for any child
of etree.ElementBase. See simple example below.
[-------------------------------------------------------------]
#!/usr/bin/python

from __future__ import print_function
from lxml import etree
import copy

class DefaultElementClass(etree.ElementBase):
def getLocalTag(self):
return etree.QName(self.tag).localname


def printInformation(x):
print(x, x.__class__, "getLocalTag" in dir(x))


a = DefaultElementClass()
printInformation(a)

#
printInformation(copy.copy(a))
printInformation(copy.deepcopy(a))
[-------------------------------------------------------------]

<?xml version="1.0"?>
<!-- generated by wxGlade 0.7.2 on Mon Jun  5 14:18:29 2017 -->

<application class="" encoding="UTF-8" for_version="2.8" header_extension=".h" indent_amount="4" indent_symbol="space" is_template="0" language="python" name="" option="0" overwrite="0" path="..py.py" source_extension=".cpp" top_window="HMIFrame" use_gettext="0" use_new_namespace="1">
    <object class="Class_HMIFrame" name="HMIFrame" base="EditFrame">
        <style>wxDEFAULT_FRAME_STYLE</style>
        <title>HMIFrame</title>
        <object class="wxBoxSizer" name="sizer_1" base="EditBoxSizer">
            <orient>wxVERTICAL</orient>
            <object class="sizeritem">
                <border>0</border>
                <option>0</option>
                <object class="wxSpinCtrl" name="spin_ctrl_1" base="EditSpinCtrl">
                    <range>0, 10000</range>
                </object>
            </object>
            <object class="sizeritem">
                <border>0</border>
                <option>0</option>
                <object class="wxCheckBox" name="checkbox_1" base="EditCheckBox">
                    <label>checkbox_1</label>
                </object>
            </object>
            <object class="sizeritem">
                <border>0</border>
                <option>0</option>
                <object class="wxStaticText" name="label_1" base="EditStaticText">
                    <attribute>1</attribute>
                    <label>GUI changed!</label>
                </object>
            </object>
        </object>
    </object>
</application>