Add the function to the apply function call stack.

        This function will be executed when apply is called. It will be executed
        in the order inserted; apply's func operates the last and return

def add_to_apply_calls(self, func, **kwargs):
        """Add the function to the apply function call stack.

        This function will be executed when apply is called. It will be executed
        in the order inserted; apply's func operates the last and return
        """
        import dask

        self.delayed_call = dask.delayed(func)(self.delayed_call, **kwargs)
        return self