old_contents: # encoding: utf-8
  
  from __future__ import unicode_literals
  
  from .base import _HasKind, _CastingKind, Field
  
  
  class Embed(_HasKind, _CastingKind, Field):
  	__foreign__ = 'object'
  	__allowed_operators__ = {'#document'}
  	
  	def __init__(self, *args, **kw):
  		if args:
  			kw['kind'], args = args[0], args[1:]
  			kw.setdefault('default', lambda: self._kind()())
  		
  		super(Embed, self).__init__(*args, **kw)
  
new_contents: # encoding: utf-8
  
  from __future__ import unicode_literals
  
  from .base import _HasKind, _CastingKind, Field
  
  
  class Embed(_HasKind, _CastingKind, Field):
  	__foreign__ = 'object'
  	__allowed_operators__ = {'#document', '$eq', '#rel'}
  	
  	def __init__(self, *args, **kw):
  		if args:
  			kw['kind'], args = args[0], args[1:]
  			kw.setdefault('default', lambda: self._kind()())
  		
  		super(Embed, self).__init__(*args, **kw)
  
subject: Allow additional operations on embeds.