from contextlib import contextmanager

@contextmanager

def scope_context(context, name, parent):

"""Context manager for setting scope on context.

Useful if ``Field`` or ``FieldSerializer`` implementations want to gather

information from related model.

:param context: ``ScopeContext`` instance.

:param name: The field name in this scope.

:param parent: The field containing model for this scope.

"""

context.name = name

context.parent = parent

try:

yield context

finally:

context.name = context.parent = None

class ScopeContext(object):

"""A scoped context.

"""

name = None

"""Name of the field while scoped."""

parent = None

"""The field containing model while scoped."""