code: def metrics():
      m1 = pd.DataFrame({"mae": [0.1], "mse": [0.2]})
      m2 = pd.DataFrame({"mae": [0.15], "mse": [0.25]})
      m3 = pd.DataFrame({"mae": [0.25], "mse": [0.35]})
      return [m1, m2, m3]
  
imports: import pytest
  import pandas
  import numpy
  from sklearn_evaluation import NotebookCollection
  from sklearn_evaluation.nb import NotebookCollection
  from IPython.display import HTML
label_desc: Use image node_id 11 for calling a global function with example usage: metrics() and returns: list