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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def get_basic_selection(self, selection=Ellipsis, out=None, fields=None):
 """Retrieve data for an item or region of the array. Parameters selection : tuple A tuple specifying the requested item or region for each dimension of the array. May be any combination of int and/or slice for multidimensional arrays. out : ndarray, optional If given, load the selected data directly into this array. fields : str or sequence of str, optional For arrays with a structured dtype, one or more fields can be specified to extract data for. Returns ------- out : ndarray A NumPy array containing the data for the requested region. Examples -------- Setup a 1-dimensional array:: Retrieve a single item:: 5 Retrieve a region via slicing:: array([0, 1, 2, 3, 4]) array([95, 96, 97, 98, 99]) array([5, 6, 7, 8, 9]) array([5, 7, 9]) Setup a 2-dimensional array:: Retrieve an item:: 22 Retrieve a region via slicing:: array([[11, 12], [21, 22]]) array([[10, 11, 12, 13, 14, 15, 16, 17, 18, 19], [20, 21, 22, 23, 24, 25, 26, 27, 28, 29]]) array([[ 1, 2], [11, 12], [21, 22], [31, 32], [41, 42], [51, 52], [61, 62], [71, 72], [81, 82], [91, 92]]) array([[ 0, 2, 4], [20, 22, 24], [40, 42, 44]]) array([[ 0, 2, 4, 6, 8], [20, 22, 24, 26, 28], [40, 42, 44, 46, 48], [60, 62, 64, 66, 68], [80, 82, 84, 86, 88]]) For arrays with a structured dtype, specific fields can be retrieved, e.g.:: array([b'aaa', b'bbb'], dtype='|S3') Notes ----- Slices with step > 1 are supported, but slices with negative step are not. Currently this method provides the implementation for accessing data via the square bracket notation (__getitem__). See :func:`__getitem__` for examples using the alternative notation. See Also -------- set_basic_selection, get_mask_selection, set_mask_selection, get_coordinate_selection, set_coordinate_selection, get_orthogonal_selection, set_orthogonal_selection, vindex, oindex, __getitem__, __setitem__ """


        # refresh metadata
        if not self._cache_metadata:
            self._load_metadata()

        # check args
        check_fields(fields, self._dtype)

        # handle zero-dimensional arrays
        if self._shape == ():
            return self._get_basic_selection_zd(selection=selection, out=out,
                                                fields=fields)
        else:
            return self._get_basic_selection_nd(selection=selection, out=out,
                                                fields=fields)