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" encoding="UTF-8" standalone="no"?>
<EtherCATConfig xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="EtherCATInfo.xsd">
  <Config>
    <Master>
      <Info>
        <Name></Name>
        <Destination>00</Destination>
        <Source>00</Source>
      </Info>
    </Master>
    <Slave>
      <Info>
        <Name>EK1100</Name>
        <PhysAddr>0</PhysAddr>
        <AutoIncAddr>0</AutoIncAddr>
        <Physics></Physics>
        <VendorId>2</VendorId>
        <ProductCode>72100946</ProductCode>
        <RevisionNo>65536</RevisionNo>
        <SerialNo>0</SerialNo>
      </Info>
    </Slave>
    <Slave>
      <Info>
        <Name>EL1088</Name>
        <PhysAddr>1</PhysAddr>
        <AutoIncAddr>0</AutoIncAddr>
        <Physics></Physics>
        <VendorId>2</VendorId>
        <ProductCode>71315538</ProductCode>
        <RevisionNo>1048576</RevisionNo>
        <SerialNo>0</SerialNo>
      </Info>
    </Slave>
    <Slave>
      <Info>
        <Name>EL2088</Name>
        <PhysAddr>2</PhysAddr>
        <AutoIncAddr>0</AutoIncAddr>
        <Physics></Physics>
        <VendorId>2</VendorId>
        <ProductCode>136851538</ProductCode>
        <RevisionNo>1048576</RevisionNo>
        <SerialNo>0</SerialNo>
      </Info>
    </Slave>
    <Slave>
      <Info>
        <Name>SanyoDenki RS2 EtherCAT</Name>
        <PhysAddr>3</PhysAddr>
        <AutoIncAddr>1</AutoIncAddr>
        <Physics></Physics>
        <VendorId>441</VendorId>
        <ProductCode>2</ProductCode>
        <RevisionNo>0</RevisionNo>
        <SerialNo>0</SerialNo>
      </Info>
    </Slave>
  </Config>
</EtherCATConfig>