code: def find_nuc_indel(gapped_seq, indel_seq):
      
      ref_indel = indel_seq[0]
      for j in range(1,len(gapped_seq)):
          if gapped_seq[j] == "-":
              ref_indel += indel_seq[j]
          else:
              break
      return ref_indel
docs: This function finds the entire indel missing in from a gapped sequence 
      compared to the indel_seqeunce. It is assumes that the sequences start
      with the first position of the gap.