def parallel_diagnostics(self, signature=None, level=1):
        """
        Print parallel diagnostic information for the given signature. If no
        signature is present it is printed for all known signatures. level is
        used to adjust the verbosity, level=1 (default) is minimal verbosity,
        and 2, 3, and 4 provide increasing levels of verbosity.
        """
        def dump(sig):
            ol = self.overloads[sig]
            pfdiag = ol.metadata.get('parfor_diagnostics', None)
            if pfdiag is None:
                msg = "No parfors diagnostic available, is 'parallel=True' set?"
                raise ValueError(msg)
            pfdiag.dump(level)
        if signature is not None:
            dump(signature)
        else:
            [dump(sig) for sig in self.signatures]

        Print parallel diagnostic information for the given signature. If no
        signature is present it is printed for all known signatures. level is
        used to adjust the verbosity, level=1 (default) is minimal verbosity,
        and 2, 3, and 4 provide increasing levels of verbosity.
        
numba/core/dispatcher.py