code: def is_valid_embedding(emb, source, target):
      
      for _ in diagnose_embedding(emb, source, target):
          return False
      return True
docs: A simple (bool) diagnostic for minor embeddings.
  
      See :func:`diagnose_embedding` for a more detailed diagnostic / more information.
  
      Args:
          emb (dict): a dictionary mapping source nodes to arrays of target nodes
          source (graph or edgelist): the graph to be embedded
          target (graph or edgelist): the graph being embedded into
  
      Returns:
          bool: True if `emb` is valid.