code: def f1(x):
      return x**2 - 2 * x - 1
  
imports: import pytest
  from math import sqrt, exp, sin, cos
  from functools import lru_cache
  from numpy.testing import assert_warns, assert_, assert_allclose, assert_equal, assert_array_equal, suppress_warnings
  import numpy
  from numpy import finfo, power, nan, isclose
  from scipy.optimize import zeros, newton, root_scalar
  from scipy._lib._util import getfullargspec_no_self
  from scipy.optimize._tstutils import get_tests, functions, fstrings
label_desc: Use image node_id 14 for calling the TestBasic obj's underlying member method code with example usage: obj.f1(x) and returns: unknown