How to use the fireworks.core.firework.Tracker function in FireWorks

user_incar_settings = {"ISMEAR": 1, "SIGMA": 0.2}
        else:
            user_incar_settings = {}

        print 'Adding more runs...'

        type_name = 'GGA+U' if 'GGA+U' in fw_spec['prev_task_type'] else 'GGA'

        snl = StructureNL.from_dict(fw_spec['mpsnl'])
        f = Composition(snl.structure.composition.reduced_formula).alphabetical_formula

        fws = []
        connections = {}

        priority = fw_spec['_priority']
        trackers = [Tracker('FW_job.out'), Tracker('FW_job.error'), Tracker('vasp.out'), Tracker('OUTCAR'), Tracker('OSZICAR')]
        trackers_db = [Tracker('FW_job.out'), Tracker('FW_job.error')]

        # run GGA static
        spec = fw_spec  # pass all the items from the current spec to the new
        spec.update({'task_type': '{} static v2'.format(type_name), '_queueadapter': QA_VASP_SMALL,
                     '_dupefinder': DupeFinderVasp().to_dict(), '_priority': priority, '_trackers': trackers})
        fws.append(
            Firework(
                [VaspCopyTask({'use_CONTCAR': True, 'skip_CHGCAR': True}), SetupStaticRunTask({"kpoints_density": static_dens, 'user_incar_settings': user_incar_settings}),
                 get_custodian_task(spec)], spec, name=get_slug(f+'--'+spec['task_type']), fw_id=-10))

        # insert into DB - GGA static
        spec = {'task_type': 'VASP db insertion', '_queueadapter': QA_DB,
                '_allow_fizzled_parents': True, '_priority': priority*2, "_dupefinder": DupeFinderDB().to_dict(), '_trackers': trackers_db}
        fws.append(
            Firework([VaspToDBTask()], spec, name=get_slug(f+'--'+spec['task_type']), fw_id=-9))

else:
            user_incar_settings = {}

        print 'Adding more runs...'

        type_name = 'GGA+U' if 'GGA+U' in fw_spec['prev_task_type'] else 'GGA'

        snl = StructureNL.from_dict(fw_spec['mpsnl'])
        f = Composition(snl.structure.composition.reduced_formula).alphabetical_formula

        fws = []
        connections = {}

        priority = fw_spec['_priority']
        trackers = [Tracker('FW_job.out'), Tracker('FW_job.error'), Tracker('vasp.out'), Tracker('OUTCAR'), Tracker('OSZICAR')]
        trackers_db = [Tracker('FW_job.out'), Tracker('FW_job.error')]

        # run GGA static
        spec = fw_spec  # pass all the items from the current spec to the new
        spec.update({'task_type': '{} static v2'.format(type_name), '_queueadapter': QA_VASP_SMALL,
                     '_dupefinder': DupeFinderVasp().to_dict(), '_priority': priority, '_trackers': trackers})
        fws.append(
            Firework(
                [VaspCopyTask({'use_CONTCAR': True, 'skip_CHGCAR': True}), SetupStaticRunTask({"kpoints_density": static_dens, 'user_incar_settings': user_incar_settings}),
                 get_custodian_task(spec)], spec, name=get_slug(f+'--'+spec['task_type']), fw_id=-10))

        # insert into DB - GGA static
        spec = {'task_type': 'VASP db insertion', '_queueadapter': QA_DB,
                '_allow_fizzled_parents': True, '_priority': priority*2, "_dupefinder": DupeFinderDB().to_dict(), '_trackers': trackers_db}
        fws.append(
            Firework([VaspToDBTask()], spec, name=get_slug(f+'--'+spec['task_type']), fw_id=-9))
        connections[-10] = -9

snl_spec['mpsnl'] = snl.as_dict()
        else:
            raise ValueError("improper use of force SNL")
        snl_spec['snlgroup_id'] = parameters['snlgroup_id']
    else:
        # add the SNL to the SNL DB and figure out duplicate group
        tasks = [AddSNLTask()]
        spec = {'task_type': 'Add to SNL database',
                'snl': snl.as_dict(), '_queueadapter': QA_DB,
                '_priority': snl_priority}
        fws.append(Firework(tasks, spec, fw_id=0,
                            name=get_slug(f + '--' + spec['task_type'])))
        connections[0] = [1]

    trackers = [Tracker('FW_job.out'), Tracker('FW_job.error'),
                Tracker('vasp.out'), Tracker('OUTCAR'), Tracker('OSZICAR'),
                Tracker('OUTCAR.relax1'), Tracker('OUTCAR.relax2')]
    trackers_db = [Tracker('FW_job.out'), Tracker('FW_job.error')]
    # run GGA structure optimization
    spec = _snl_to_spec(snl, enforce_gga=True, parameters=parameters)
    spec.update(snl_spec)
    spec['_priority'] = priority
    spec['_queueadapter'] = QA_VASP
    spec['_trackers'] = trackers
    tasks = [VaspWriterTask(), get_custodian_task(spec)]
    fws.append(Firework(tasks, spec, name=get_slug(f + '--' + spec['task_type']), fw_id=1))

    # insert into DB - GGA structure optimization
    spec = {'task_type': 'VASP db insertion', '_priority': priority*2,
            '_allow_fizzled_parents': True, '_queueadapter': QA_DB, 
            "_dupefinder": DupeFinderDB().to_dict(), '_trackers': trackers_db}
    fws.append(Firework([VaspToDBTask()], spec, fw_id=2,

else:
            raise ValueError("improper use of force SNL")
        snl_spec['snlgroup_id'] = parameters['snlgroup_id']
    else:
        # add the SNL to the SNL DB and figure out duplicate group
        tasks = [AddSNLTask()]
        spec = {'task_type': 'Add to SNL database',
                'snl': snl.as_dict(), '_queueadapter': QA_DB,
                '_priority': snl_priority}
        fws.append(Firework(tasks, spec, fw_id=0,
                            name=get_slug(f + '--' + spec['task_type'])))
        connections[0] = [1]

    trackers = [Tracker('FW_job.out'), Tracker('FW_job.error'),
                Tracker('vasp.out'), Tracker('OUTCAR'), Tracker('OSZICAR'),
                Tracker('OUTCAR.relax1'), Tracker('OUTCAR.relax2')]
    trackers_db = [Tracker('FW_job.out'), Tracker('FW_job.error')]
    # run GGA structure optimization
    spec = _snl_to_spec(snl, enforce_gga=True, parameters=parameters)
    spec.update(snl_spec)
    spec['_priority'] = priority
    spec['_queueadapter'] = QA_VASP
    spec['_trackers'] = trackers
    tasks = [VaspWriterTask(), get_custodian_task(spec)]
    fws.append(Firework(tasks, spec, name=get_slug(f + '--' + spec['task_type']), fw_id=1))

    # insert into DB - GGA structure optimization
    spec = {'task_type': 'VASP db insertion', '_priority': priority*2,
            '_allow_fizzled_parents': True, '_queueadapter': QA_DB, 
            "_dupefinder": DupeFinderDB().to_dict(), '_trackers': trackers_db}
    fws.append(Firework([VaspToDBTask()], spec, fw_id=2,
                        name=get_slug(f + '--' + spec['task_type'])))

def add_trackers(original_wf, tracked_files=None, nlines=25):
    """
    Every FireWork that runs VASP also tracks the OUTCAR, OSZICAR, etc using FWS Trackers.

    Args:
        original_wf (Workflow)
        tracked_files (list) : list of files to be tracked
        nlines (int): number of lines at the end of files to be tracked
    """
    if tracked_files is None:
        tracked_files = ["OUTCAR", "OSZICAR"]
    trackers = [Tracker(f, nlines=nlines, allow_zipped=True) for f in tracked_files]
    wf_dict = original_wf.to_dict()
    for idx_fw, idx_t in get_fws_and_tasks(original_wf, task_name_constraint="RunVasp"):
        if "_trackers" in wf_dict["fws"][idx_fw]["spec"]:
            wf_dict["fws"][idx_fw]["spec"]["_trackers"].extend(trackers)
        else:
            wf_dict["fws"][idx_fw]["spec"]["_trackers"] = trackers
    return Workflow.from_dict(wf_dict)

def from_dict(cls, m_dict):
        return Tracker(m_dict['filename'], m_dict['nlines'], m_dict.get('content', ''),
                       m_dict.get('allow_zipped', False))

def from_dict(cls, m_dict):
        fworker = FWorker.from_dict(m_dict['fworker']) if m_dict['fworker'] else None
        action = FWAction.from_dict(m_dict['action']) if m_dict.get('action') else None
        trackers = [Tracker.from_dict(f) for f in m_dict['trackers']] if m_dict.get('trackers') else None
        return Launch(m_dict['state'], m_dict['launch_dir'], fworker,
                      m_dict['host'], m_dict['ip'], trackers, action,
                      m_dict['state_history'], m_dict['launch_id'], m_dict['fw_id'])