Generate a placeholder name to use while updating WeldObject.

        Parameters
        ----------
        readable_text : str, optional
            Appended to the name for a more understandable placeholder.

        Returns
        -------
        str
            Placeholder.

def _generate_placeholder(readable_text=None):
        """Generate a placeholder name to use while updating WeldObject.

        Parameters
        ----------
        readable_text : str, optional
            Appended to the name for a more understandable placeholder.

        Returns
        -------
        str
            Placeholder.

        """
        name = '_interm_' + str(Cache._counter)
        Cache._counter += 1

        if readable_text is not None:
            assert isinstance(readable_text, str)
            name += '_' + readable_text

        return name