code: def shortest_path(creation_sequence, u, v):
      """
      Find the shortest path between u and v in a
      threshold graph G with the given creation_sequence.
  
      For an unlabeled creation_sequence, the vertices
      u and v must be integers in (0,len(sequence)) referring
      to the position of the desired vertices in the sequence.
  
      For a labeled creation_sequence, u and v are labels of vertices.
  
      Use cs=creation_sequence(degree_sequence,with_labels=True)
      to convert a degree sequence to a creation sequence.
  
      Returns a list of vertices from u to v.
      Example: if they are neighbors, it returns [u,v]
      """
      # Turn input sequence into a labeled creation sequence
      first = creation_sequence[0]
      if isinstance(first, str):  # creation sequence
          cs = [
              (i, creation_sequence[i])
              for i in range(len(creation_sequence))
          ]
      elif isinstance(first, tuple):  # labeled creation sequence
          cs = creation_sequence[:]
      elif isinstance(first, int):  # compact creation sequence
          ci = uncompact(creation_sequence)
          cs = [(i, ci[i]) for i in range(len(ci))]
      else:
          raise TypeError("Not a valid creation sequence type")
  
      verts = [s[0] for s in cs]
      if v not in verts:
          raise ValueError(
              f"Vertex {v} not in graph from creation_sequence"
          )
      if u not in verts:
          raise ValueError(
              f"Vertex {u} not in graph from creation_sequence"
          )
      # Done checking
      if u == v:
          return [u]
  
      uindex = verts.index(u)
      vindex = verts.index(v)
      bigind = max(uindex, vindex)
      if cs[bigind][1] == "d":
          return [u, v]
      # must be that cs[bigind][1]=='i'
      cs = cs[bigind:]
      while cs:
          vert = cs.pop()
          if vert[1] == "d":
              return [u, vert[0], v]
      # All after u are type 'i' so no connection
      return -1
  
imports: from math import sqrt
  import networkx
  from networkx.utils import py_random_state
label_desc: Use image node_id 18 for calling a global function with example usage: shortest_path(creation_sequence, u, v) and returns: unknown, list, list, list