def setBreak(self,breakFlag = True):
        """Method to invoke the Python pdb debugger when this element is
           about to be parsed. Set ``breakFlag`` to True to enable, False to
           disable.
        """
        if breakFlag:
            _parseMethod = self._parse
            def breaker(instring, loc, doActions=True, callPreParse=True):
                import pdb
                pdb.set_trace()
                return _parseMethod( instring, loc, doActions, callPreParse )
            breaker._originalParseMethod = _parseMethod
            self._parse = breaker
        else:
            if hasattr(self._parse,"_originalParseMethod"):
                self._parse = self._parse._originalParseMethod
        return self
Method to invoke the Python pdb debugger when this element is
           about to be parsed. Set ``breakFlag`` to True to enable, False to
           disable.
        
stackoverflow/venv/lib/python3.6/site-packages/pip-19.0.3-py3.6.egg/pip/_vendor/pyparsing.py