Find indices where elements should be inserted to maintain order.

        .. versionadded:: 0.24.0

        Find the indices into a sorted array `self` (a) such that, if the
        corresponding elements in `value` were inserted before the indices,
        the order of `self` would be preserved.

        Assuming that `self` is sorted:

        ======  ================================
        `side`  returned index `i` satisfies
        ======  ================================
        left    ``self[i-1] < value <= self[i]``
        right   ``self[i-1] <= value < self[i]``
        ======  ================================

        Parameters
        ----------
        value : array_like
            Values to insert into `self`.
        side : {'left', 'right'}, optional
            If 'left', the index of the first suitable location found is given.
            If 'right', return the last such index.  If there is no suitable
            index, return either 0 or N (where N is the length of `self`).
        sorter : 1-D array_like, optional
            Optional array of integer indices that sort array a into ascending
            order. They are typically the result of argsort.

        Returns
        -------
        array of ints
            Array of insertion points with the same shape as `value`.

        See Also
        --------
        numpy.searchsorted : Similar method from NumPy.

def searchsorted(self, value, side="left", sorter=None):
        """
        Find indices where elements should be inserted to maintain order.

        .. versionadded:: 0.24.0

        Find the indices into a sorted array `self` (a) such that, if the
        corresponding elements in `value` were inserted before the indices,
        the order of `self` would be preserved.

        Assuming that `self` is sorted:

        ======  ================================
        `side`  returned index `i` satisfies
        ======  ================================
        left    ``self[i-1] < value <= self[i]``
        right   ``self[i-1] <= value < self[i]``
        ======  ================================

        Parameters
        ----------
        value : array_like
            Values to insert into `self`.
        side : {'left', 'right'}, optional
            If 'left', the index of the first suitable location found is given.
            If 'right', return the last such index.  If there is no suitable
            index, return either 0 or N (where N is the length of `self`).
        sorter : 1-D array_like, optional
            Optional array of integer indices that sort array a into ascending
            order. They are typically the result of argsort.

        Returns
        -------
        array of ints
            Array of insertion points with the same shape as `value`.

        See Also
        --------
        numpy.searchsorted : Similar method from NumPy.
        """
        # Note: the base tests provided by pandas only test the basics.
        # We do not test
        # 1. Values outside the range of the `data_for_sorting` fixture
        # 2. Values between the values in the `data_for_sorting` fixture
        # 3. Missing values.
        arr = self.astype(object)
        return arr.searchsorted(value, side=side, sorter=sorter)