def sim(nodes1, nodes2):
    
    """
    Parameters
    ----------
    nodes1: Top K biomarkes of GNN Structure 1.
    nodes2: Top K biomarkes of GNN Structure 2.
    
    Description
    ----------
    Returns the overlap ratio between Top K biomarkes of two GNN architectures.
    """
    
    counter = 0
    for i in nodes1:
      for k in nodes2:
        if i==k:
          counter+=1
    return counter/len(nodes1)