Returns list of variables of the network

        Example
        -------
        >>> reader = PomdpXReader("pomdpx.xml")
        >>> reader.get_variables()
        {'StateVar': [
                        {'vnamePrev': 'rover_0',
                         'vnameCurr': 'rover_1',
                         'ValueEnum': ['s0', 's1', 's2'],
                         'fullyObs': True},
                        {'vnamePrev': 'rock_0',
                         'vnameCurr': 'rock_1',
                         'fullyObs': False,
                         'ValueEnum': ['good', 'bad']}],
                        'ObsVar': [{'vname': 'obs_sensor',
                                    'ValueEnum': ['ogood', 'obad']}],
                        'RewardVar': [{'vname': 'reward_rover'}],
                        'ActionVar': [{'vname': 'action_rover',
                                       'ValueEnum': ['amw', 'ame',
                                                     'ac', 'as']}]
                        }

def get_variables(self):
        """
        Returns list of variables of the network

        Example
        -------
        >>> reader = PomdpXReader("pomdpx.xml")
        >>> reader.get_variables()
        {'StateVar': [
                        {'vnamePrev': 'rover_0',
                         'vnameCurr': 'rover_1',
                         'ValueEnum': ['s0', 's1', 's2'],
                         'fullyObs': True},
                        {'vnamePrev': 'rock_0',
                         'vnameCurr': 'rock_1',
                         'fullyObs': False,
                         'ValueEnum': ['good', 'bad']}],
                        'ObsVar': [{'vname': 'obs_sensor',
                                    'ValueEnum': ['ogood', 'obad']}],
                        'RewardVar': [{'vname': 'reward_rover'}],
                        'ActionVar': [{'vname': 'action_rover',
                                       'ValueEnum': ['amw', 'ame',
                                                     'ac', 'as']}]
                        }
        """
        self.variables = defaultdict(list)
        for variable in self.network.findall('Variable'):
            _variables = defaultdict(list)
            for var in variable.findall('StateVar'):
                state_variables = defaultdict(list)
                state_variables['vnamePrev'] = var.get('vnamePrev')
                state_variables['vnameCurr'] = var.get('vnameCurr')
                if var.get('fullyObs'):
                    state_variables['fullyObs'] = True
                else:
                    state_variables['fullyObs'] = False
                state_variables['ValueEnum'] = []
                if var.find('NumValues') is not None:
                    for i in range(0, int(var.find('NumValues').text)):
                        state_variables['ValueEnum'].append('s' + str(i))
                if var.find('ValueEnum') is not None:
                    state_variables['ValueEnum'] = \
                        var.find('ValueEnum').text.split()
                _variables['StateVar'].append(state_variables)

            for var in variable.findall('ObsVar'):
                obs_variables = defaultdict(list)
                obs_variables['vname'] = var.get('vname')
                obs_variables['ValueEnum'] = \
                    var.find('ValueEnum').text.split()
                _variables['ObsVar'].append(obs_variables)

            for var in variable.findall('ActionVar'):
                action_variables = defaultdict(list)
                action_variables['vname'] = var.get('vname')
                action_variables['ValueEnum'] = \
                    var.find('ValueEnum').text.split()
                _variables['ActionVar'].append(action_variables)

            for var in variable.findall('RewardVar'):
                reward_variables = defaultdict(list)
                reward_variables['vname'] = var.get('vname')
                _variables['RewardVar'].append(reward_variables)

            self.variables.update(_variables)

        return self.variables