<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def get_header(self, request):
 """ Extracts the header containing the JSON web token from the given request. """

        header = request.META.get('HTTP_AUTHORIZATION')

        if isinstance(header, str):
            # Work around django test client oddness
            header = header.encode(HTTP_HEADER_ENCODING)

        return header