Cast to a NumPy array or IntegerArray with 'dtype'.

        Parameters
        ----------
        dtype : str or dtype
            Typecode or data-type to which the array is cast.
        copy : bool, default True
            Whether to copy the data, even if not necessary. If False,
            a copy is made only if the old dtype does not match the
            new dtype.

        Returns
        -------
        array : ndarray or IntegerArray
            NumPy ndarray or IntergerArray with 'dtype' for its dtype.

        Raises
        ------
        TypeError
            if incompatible type with an IntegerDtype, equivalent of same_kind
            casting

def astype(self, dtype, copy=True):
        """
        Cast to a NumPy array or IntegerArray with 'dtype'.

        Parameters
        ----------
        dtype : str or dtype
            Typecode or data-type to which the array is cast.
        copy : bool, default True
            Whether to copy the data, even if not necessary. If False,
            a copy is made only if the old dtype does not match the
            new dtype.

        Returns
        -------
        array : ndarray or IntegerArray
            NumPy ndarray or IntergerArray with 'dtype' for its dtype.

        Raises
        ------
        TypeError
            if incompatible type with an IntegerDtype, equivalent of same_kind
            casting
        """

        # if we are astyping to an existing IntegerDtype we can fastpath
        if isinstance(dtype, _IntegerDtype):
            result = self._data.astype(dtype.numpy_dtype, copy=False)
            return type(self)(result, mask=self._mask, copy=False)

        # coerce
        data = self._coerce_to_ndarray()
        return astype_nansafe(data, dtype, copy=None)