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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def create_segs_from_cats_job(cp, out_dir, ifo_string, tags=None):
 """ This function creates the CondorDAGJob that will be used to run ligolw_segments_from_cats as part of the workflow Parameters cp : pycbc.workflow.configuration.WorkflowConfigParser The in-memory representation of the configuration (.ini) files out_dir : path Directory in which to put output files ifo_string : string String containing all active ifos, ie. "H1L1V1" tag : list of strings, optional (default=None) Use this to specify a tag(s). This can be used if this module is being called more than once to give call specific configuration (by setting options in [workflow-datafind-${TAG}] rather than [workflow-datafind]). This is also used to tag the Files returned by the class to uniqueify the Files and uniqueify the actual filename. FIXME: Filenames may not be unique with current codes! Returns -------- job : Job instance The Job instance that will run segments_from_cats jobs """

    if tags is None:
        tags = []

    seg_server_url = cp.get_opt_tags("workflow-segments",
                                   "segments-database-url", tags)
    veto_def_file = cp.get_opt_tags("workflow-segments",
                                  "segments-veto-definer-file", tags)

    job = Executable(cp, 'segments_from_cats', universe='local',
                               ifos=ifo_string, out_dir=out_dir, tags=tags)
    job.add_opt('--separate-categories')
    job.add_opt('--segment-url', seg_server_url)

    job.add_opt('--veto-file', veto_def_file)
    # FIXME: Would like the proxy in the Workflow instance
    # FIXME: Explore using the x509 condor commands
    # If the user has a proxy set in the environment, add it to the job
    return job