Context manager for encapsulating code in a single undo.
Use in a with statement Wrapper for cmds.undoInfo(openChunk=1)/cmds.undoInfo(closeChunk=1)
>>> import pymel.core as pm
>>> pm.ls("MyNode*", type='transform')
[]
>>> with pm.UndoChunk():
... res = pm.createNode('transform', name="MyNode1")
... res = pm.createNode('transform', name="MyNode2")
... res = pm.createNode('transform', name="MyNode3")
>>> pm.ls("MyNode*", type='transform')
[nt.Transform(u'MyNode1'), nt.Transform(u'MyNode2'), nt.Transform(u'MyNode3')]
>>> pm.undo() # Due to the undo chunk, all three are undone at once
>>> pm.ls("MyNode*", type='transform')
[]