'If the original headers were:
{\'Abc-Def\': \'F00N3s\'}
This will return:
{\'abc-def\': \'F00N3s\'}
The only thing that changes is the header name.'

@memoized
def get_lower_case_headers(self):

    return Headers([(k.lower(), v) for (k, v) in self.headers.iteritems()])
