code: def fun_gas(self, x, y):
      alpha = 0.8
      return np.vstack(
          (y[1], -2 * x * y[1] * (1 - alpha * y[0]) ** -0.5)
      )
  
imports: import numpy
  from .common import Benchmark, safe_import
  from scipy.integrate import quad, cumulative_simpson
label_desc: Use image node_id 7 for calling the SolveBVP obj's underlying member method code with example usage: obj.fun_gas(x, y) and returns: np