How to use the saspy.sasproccommons.SASProcCommons._stmt_check function in saspy

kwargs = SASProcCommons._processNominals(self, kwargs, data)
            t_str, tcls_str = SASProcCommons._target_stmt(self, kwargs['target'])
            i_str, icls_str = SASProcCommons._input_stmt(self, kwargs['input'])
            kwargs['model'] = str(t_str + ' = ' + i_str)
            if len(icls_str) > 0:
                kwargs['cls'] = str(tcls_str + " " + icls_str)
            legal_set.add('cls')
            drop_target = kwargs.pop('target', None)
            drop_input = kwargs.pop('input', None)
            self.logger.debug(drop_target)
            self.logger.debug(drop_input)

        elif {'target'}.intersection(required_set) and 'model' in kwargs.keys() and 'target' not in kwargs.keys():
            SASProcCommons._convert_model_to_target(self)

        verifiedKwargs = SASProcCommons._stmt_check(self, required_set, legal_set, kwargs)
        obj1 = []
        nosub = False
        objname = ''
        log = ''
        if len(verifiedKwargs):
            objname = procname[:3].lower() + self.sas._objcnt()  # translate to a libname so needs to be less than 8
            code = SASProcCommons._makeProcCallMacro(self, objtype, objname, data, verifiedKwargs)
            self.logger.debug(procname + " macro submission: " + str(code))
            if not self.sas.nosub:
                ll = self.sas.submit(code, "text")
                log = ll['LOG']
                error = SASProcCommons._errorLog(self, log)
                isinstance(error, str)
                if len(error) > 1:
                    RuntimeWarning("ERRORS found in SAS log: \n%s" % error)
                    return SASresults(obj1, self.sas, objname, nosub, log)

proc_kwargs = dict(
            cls=' '.join(sets['classes']),
            var=' '.join(sets['vars']),
            table=table
        )

        # permit additional valid options if passed; for now, just 'where'
        proc_kwargs.update(kwargs)

        # we can't easily use the SASProcCommons approach for submiting, 
        # since this is merely an output / display proc for us;
        # but we can at least use it to check valid options in the canonical saspy way
        required_options = {'cls', 'var', 'table'}
        allowed_options = {'cls', 'var', 'table', 'where'}
        verifiedKwargs = sp.sasproccommons.SASProcCommons._stmt_check(self, required_options, allowed_options,
                                                                      proc_kwargs)

        if (_output_type == 'Pandas'):
            # for pandas, use the out= directive
            code = "proc tabulate data=%s.%s %s out=temptab;\n" % (
            self.data.libref, self.data.table, self.data._dsopts())
        else:
            code = "proc tabulate data=%s.%s %s;\n" % (self.data.libref, self.data.table, self.data._dsopts())

        # build the code
        for arg, value in verifiedKwargs.items():
            code += "  %s %s;\n" % (arg == 'cls' and 'class' or arg, value)
        code += "run;"

        # teach_me_SAS
        if self.sas.nosub: