code: def plot_gp(x, mu, var, color, label):
      plt.plot(x, mu, color=color, lw=2, label=label)
      plt.fill_between(
          x[:, 0],
          (mu - 2 * np.sqrt(var))[:, 0],
          (mu + 2 * np.sqrt(var))[:, 0],
          color=color,
          alpha=0.4,
      )
  
imports: import matplotlib.pyplot
  import numpy
  import gpflow
  from gpflow.ci_utils import reduce_in_tests
label_desc: Use image node_id 1 for calling a global function with example usage: plot_gp(x, mu, var, color, label) without return types