def stdlib(self):
        """
        A boolean flag. ``True`` if frame is in stdlib.

        :type: bool
        """
        if self.module == 'pkg_resources' or self.module.startswith('pkg_resources.'):
            return False
        elif self.filename.startswith(SITE_PACKAGES_PATHS):
            # if it's in site-packages then its definitely not stdlib
            return False
        elif self.filename.startswith(SYS_PREFIX_PATHS):
            return True
        else:
            return False
A boolean flag. ``True`` if frame is in stdlib.

        :type: bool