code: def embed(self, rel, target, wrap=False):
          
          new_embed = target.as_object()
          self._add_rel('_embedded', rel, new_embed, wrap)
  
          if self.draft.automatic_link:
              self.add_link(rel, target, wrap)
  
          return self
docs: Embeds a document inside this document.
  
          This method embeds the given document in this document with the given
          ``rel``. If one or more documents have already been embedded for that
          ``rel``, the new document will be embedded in addition to those
          documents.
  
          This method returns self, allowing it to be chained with additional
          method calls.
  
          Arguments:
  
          - ``rel``: a string specifying the link relationship type of the
            embedded resource. ``rel`` should be a well-known link relation name
            from the IANA registry
            (http://www.iana.org/assignments/link-relations/link-relations.xml),
            a full URI, or a CURIE.
          - ``target``: a ``Builder`` instance or a ``dougrain.Document``
            instance that will be embedded in this document.
          - ``wrap``: Defaults to False, but if True, specifies that the embedded
            resource object should be initally wrapped in a JSON array even if it
            is the first embedded resource for the given ``rel``.
  
          Unlike ``dougrain.Document.embed``, this method does not detect
          equivalence between relationship types with different representations.
  
          WARNING: ``target`` should not be identical to ``self`` or any document
          that embeds ``self``.