code: def sequence_to_string(
      a_list,
      open_bracket_char='[',
      close_bracket_char=']',
      delimiter=", "
  ):
      
      return "%s%s%s" % (
          open_bracket_char,
          delimiter.join(
              local_to_str(x)
              for x in a_list
          ),
          close_bracket_char
      )
docs: a dedicated function that turns a list into a comma delimited string
      of items converted.  This method will flatten nested lists.