Capture variables created within this scope as
template.variable_scope is active.
This scope is intended as a compatibility measure, allowing a trackable
object to add dependencies on variables created in a block of code which is
not aware of object-based saving (and instead uses variable names
heavily). This is how
Template objects add dependencies on variables and
Templates. Where possible, use
Templateobject to register dependencies with.
None (when used as a context manager).