Mask doesn't work on latest Xcode and swift

error as follows:

(lldb) mask self.testView error: error: use of undeclared identifier 'self' error: error: use of undeclared identifier 'None' error: error: use of undeclared identifier 'None' error: error: use of undeclared identifier 'None' Traceback (most recent call last): File "/usr/local/opt/chisel/libexec/fblldb.py", line 83, in runCommand command.run(args, options) File "/usr/local/Cellar/chisel/1.5.0/libexec/commands/FBDisplayCommands.py", line 153, in run viewHelpers.maskView(viewOrLayer, options.color, options.alpha) File "/usr/local/opt/chisel/libexec/fblldbviewhelpers.py", line 25, in maskView origin = convertPoint(0, 0, viewOrLayer, window) File "/usr/local/opt/chisel/libexec/fblldbviewhelpers.py", line 47, in convertPoint fromLayer = convertToLayer(fromViewOrLayer) File "/usr/local/opt/chisel/libexec/fblldbviewhelpers.py", line 52, in convertToLayer if fb.evaluateBooleanExpression('[(id)%s isKindOfClass:(Class)[CALayer class]]' % viewOrLayer): File "/usr/local/opt/chisel/libexec/fblldbbase.py", line 84, in evaluateBooleanExpression return (int(evaluateIntegerExpression('(BOOL)(' + expression + ')', printErrors)) != 0) File "/usr/local/opt/chisel/libexec/fblldbbase.py", line 76, in evaluateIntegerExpression output = evaluateExpression('(int)(' + expression + ')', printErrors).replace(''', '') AttributeError: 'NoneType' object has no attribute 'replace'