code: def _scalar_func_1(self, s):
      self.fcount += 1
      p = -s - s**3 + s**4
      dp = -1 - 3 * s**2 + 4 * s**3
      return p, dp
  
imports: from numpy.testing import assert_, assert_equal, assert_array_almost_equal, assert_array_almost_equal_nulp, assert_warns, suppress_warnings
  import scipy.optimize.linesearch
  from scipy.optimize.linesearch import LineSearchWarning
  import numpy
label_desc: Use image node_id 1 for calling the TestLineSearch obj's underlying member method code with example usage: obj._scalar_func_1(s) and returns: p,  dp