keras/src/backend/numpy/numpy.py/std
def std(x, axis=None, keepdims=False):
    axis = standardize_axis_for_numpy(axis)
    x = convert_to_tensor(x)
    ori_dtype = standardize_dtype(x.dtype)
    if "int" in ori_dtype or ori_dtype == "bool":
        x = x.astype(config.floatx())
    return np.std(x, axis=axis, keepdims=keepdims)