code: def find_otu(otuid, tree):
      
      for m in re.finditer(otuid, tree):
          before, after = tree[m.start()-1], tree[m.start()+len(otuid)]
          if before in ["(", ",", ")"] and after in [":", ";"]:
              return m.start()
      return None
docs: Find an OTU ID in a Newick-format tree.
      Return the starting position of the ID or None if not found.