Method insert

traitlets/config/loader.py:150–153

(self, index: int, other: t.Any)

            return self.get_value(other)

    def insert(self, index: int, other: t.Any) -> None:
        if not isinstance(index, int):
            raise TypeError("An integer is required")
        self._inserts.append((index, other))

    # dict methods
    # update is used for both dict and set