code: def _lob_start_handler(c, ctx):
      
      assert c == _OPEN_BRACE
      c, self = yield
      trans = ctx.immediate_transition(self)
      quotes = 0
      while True:
          if c in _WHITESPACE:
              if quotes > 0:
                  _illegal_character(c, ctx)
          elif c == _DOUBLE_QUOTE:
              if quotes > 0:
                  _illegal_character(c, ctx)
              ctx.set_ion_type(IonType.CLOB).set_unicode(quoted_text=True)
              yield ctx.immediate_transition(_short_string_handler(c, ctx))
          elif c == _SINGLE_QUOTE:
              if not quotes:
                  ctx.set_ion_type(IonType.CLOB).set_unicode(quoted_text=True)
              quotes += 1
              if quotes == 3:
                  yield ctx.immediate_transition(_long_string_handler(c, ctx))
          else:
              yield ctx.immediate_transition(_blob_end_handler(c, ctx))
          c, _ = yield trans
docs: Handles tokens that begin with two open braces.