docs: def validate_word_size(word_size, BLAST_SETS):
      """Validate word size in blast/tblastn form.  """
  
      blast_min_int_word_size = BLAST_SETS.min_word_size
      blast_max_int_word_size = BLAST_SETS.max_word_size
      blast_word_size_error = BLAST_SETS.get_word_size_error()
  
      try:
          if len(word_size) <= 0:
              raise forms.ValidationError(blast_word_size_error)
  
          int_word_size = int(word_size)
  
          if int_word_size < blast_min_int_word_size:
              raise forms.ValidationError(blast_word_size_error)
  
          if int_word_size >= blast_max_int_word_size:
              raise forms.ValidationError(blast_word_size_error)
  
      except:
          raise forms.ValidationError(blast_word_size_error)
  
      return int_word_size