init context may cause memory leak

[lin344902118]

dsl_parser/framework/parser.py between line 123 to 133.
def _traverse_element_cls(self,
element_cls,
name,
value,
parent_element):
element = element_cls(name=name,
initial_value=value,
context=self)
self._add_element(element, parent=parent_element)
self._traverse_schema(schema=element_cls.schema,
parent_element=element)
When initial element，context reference to itself, this may cause memory leak.Because circular reference exist，memory can not be collect by python garbage。

[lin344902118]

I think should import gc and exec gc.collect to free the memory.