code: def _convert_hbf_meta_val_for_xml(key, val):
      
      if isinstance(val, list):
          return [_convert_hbf_meta_val_for_xml(key, i) for i in val]
      is_literal = True
      content = None
      if isinstance(val, dict):
          ret = val
          if '@href' in val:
              is_literal = False
          else:
              content = val.get('$')
              if isinstance(content, dict) and _contains_hbf_meta_keys(val):
                  is_literal = False
      else:
          ret = {}
          content = val
      if is_literal:
          ret.setdefault('@xsi:type', 'nex:LiteralMeta')
          ret.setdefault('@property', key)
          if content is not None:
              ret.setdefault('@datatype', _python_instance_to_nexml_meta_datatype(content))
          if ret is not val:
              ret['$'] = content
      else:
          ret.setdefault('@xsi:type', 'nex:ResourceMeta')
          ret.setdefault('@rel', key)
      return ret
docs: Convert to a BadgerFish-style dict for addition to a dict suitable for
      addition to XML tree or for v1.0 to v0.0 conversion.