(slice(None, None, None), slice(0, 10, None))

This is a tuple of two slice objects. The first slice object represents all elements along the first axis (i.e., all rows), and the second slice object represents the first 10 elements along the second axis (i.e., the first 10 columns). This tuple can be used to slice a two-dimensional array or matrix to select the first 10 columns of all rows.