def __getitem__(self, slice_: Union[str, Tuple[Union[int, np.ndarray, slice], Union[int, np.ndarray, slice]]]) -> np.ndarray:
if type(slice_) is str:<EOL><INDENT>return self.layers[slice_]<EOL><DEDENT>else:<EOL><INDENT>return self.layers["<STR_LIT>"][slice_]<EOL><DEDENT>
Get a slice of the main matrix.
Args:
        slice:		A 2D slice object (see http://docs.h5py.org/en/latest/high/dataset.html) or np.ndarrays or ints
Returns:
        A numpy matrix