'Helper function to create a set of capa problems to test against.
Creates four blocks total.'

def _create_capa_problems(self):

    self.problem_type_lookup = {}
    for problem_type in self.problem_types:
        block = self.make_block('problem', self.library, data=self._get_capa_problem_type_xml(*problem_type))
        self.problem_type_lookup[block.location] = problem_type
