text: import matplotlib.pyplot as plt
  import numpy as np
  from pycalphad import Database, Model
  from pycalphad.core.utils import make_callable
  import pycalphad.variables as v
  
  db = Database('Fe-C_Fei_Brosh_2014_09.TDB')
  mod = Model(db, ['FE', 'C', 'VA'], 'FCC_A1')
  from pycalphad.core.energy_surf import energy_surf
  data = energy_surf(db, ['FE', 'C', 'VA'], ['FCC_A1'], output='GM',\
                           T=np.linspace(300.0, 1200.0, num=10), P=np.logspace(5, 10, num=10), pdens=10)
  data.to_csv('FeC-energies.csv')
  