How to use the presto.filterbank.FilterbankFile function in presto

def inject(infile, outfn, prof, period, dm, nbitsout=None, 
           block_size=BLOCKSIZE, pulsar_only=False, inplace=False):
    if isinstance(infile, filterbank.FilterbankFile):
        fil = infile
    elif inplace:
        fil = filterbank.FilterbankFile(infile, 'readwrite')
    else:
        fil = filterbank.FilterbankFile(infile, 'read')
    print("Injecting pulsar signal into: %s" % fil.filename)
    if False:
        delays = psr_utils.delay_from_DM(dm, fil.frequencies)
        delays -= delays[np.argmax(fil.frequencies)]
        get_phases = lambda times: (times-delays)/period % 1
    else:
        get_phases = lambda times: times/period % 1

    # Create the output filterbank file
    if nbitsout is None:
        nbitsout = fil.nbits
    if inplace:
        warnings.warn("Injecting pulsar signal *in-place*")
        outfil = fil

def main():
    fn = args.infile
    if args.inplace:
        fil = filterbank.FilterbankFile(fn, mode='readwrite')
    else:
        fil = filterbank.FilterbankFile(fn, mode='read')
    if args.inprof is not None:
        warnings.warn("Saved profiles already may be tuned to a particular " \
                        "DM, period and filterbank file (freq, nchans, " \
                        "tsamp, etc).")
        prof = load_profile(args.inprof)
    else:
        prof = make_profile(args.vonmises)
        prof = apply_dm(prof, args.period, args.dm, \
                        fil.foff, fil.frequencies, fil.tsamp)
        scale_profile(prof, args.scale_name, args.scale_cfgstrs, fil)
        if args.outprof is not None:
            save_profile(prof, args.outprof)

    outfn = args.outname % fil.header

"Check lo/hi frequencies." % new_nchans)

    print("Will extract")
    print("    %d bins (%d to %d incl.)" % (new_nspec, startbin, endbin-1))
    print("    (Original num bins: %d)" % fil.nspec)
    print("    %d channels (%d to %d incl.)" % (new_nchans, lochan, hichan-1))
    print("    (Original num chans: %d)" % fil.nchans)

    # Create output file
    outfn = options.outname % fil.header
    print("Creating out file: %s" % outfn)
    outhdr = copy.deepcopy(fil.header)
    outhdr['nchans'] = new_nchans
    outhdr['fch1'] = fil.frequencies[lochan]
    filterbank.create_filterbank_file(outfn, outhdr, nbits=fil.nbits)
    outfil = filterbank.FilterbankFile(outfn, mode='write')

    # Write data
    sys.stdout.write(" %3.0f %%\r" % 0)
    sys.stdout.flush()
    nblocks = int(new_nspec/options.block_size)
    remainder = new_nspec % options.block_size
    oldprogress = -1
    for iblock in np.arange(nblocks):
        lobin = iblock*options.block_size + startbin
        hibin = lobin+options.block_size
        spectra = fil.get_spectra(lobin, hibin)
        spectra = spectra[:,lochan:hichan] # restrict channels
        outfil.append_spectra(spectra)
        progress = int(100.0*((hibin-startbin)/new_nspec))
        if progress > oldprogress: 
            sys.stdout.write(" %3.0f %%\r" % progress)

def inject(infile, outfn, prof, period, dm, nbitsout=None, 
           block_size=BLOCKSIZE, pulsar_only=False, inplace=False):
    if isinstance(infile, filterbank.FilterbankFile):
        fil = infile
    elif inplace:
        fil = filterbank.FilterbankFile(infile, 'readwrite')
    else:
        fil = filterbank.FilterbankFile(infile, 'read')
    print("Injecting pulsar signal into: %s" % fil.filename)
    if False:
        delays = psr_utils.delay_from_DM(dm, fil.frequencies)
        delays -= delays[np.argmax(fil.frequencies)]
        get_phases = lambda times: (times-delays)/period % 1
    else:
        get_phases = lambda times: times/period % 1

    # Create the output filterbank file
    if nbitsout is None:
        nbitsout = fil.nbits
    if inplace:
        warnings.warn("Injecting pulsar signal *in-place*")
        outfil = fil
    else:
        # Start an output file

def main():
    infn = args[0]
    print("Reading filterbank file (%s)" % infn)
    fil = filterbank.FilterbankFile(infn)
    if options.start_time is None:
        startbin = 0
    else:
        startbin = int(np.round(options.start_time/fil.tsamp))
    if options.end_time is None:
        endbin = fil.nspec
    else:
        endbin = int(np.round(options.end_time/fil.tsamp))+1

    new_nspec = endbin-startbin
    if new_nspec <= 0:
        raise ValueError("Bad number of spectra to be written (%d). " \
                            "Check start/end times." % new_nspec)
   
    # Determine lo/hi channels to write to file
    # If high frequencies come first in spectra 'hichan' refers to 

def main():
    fn = args.infile
    if args.inplace:
        fil = filterbank.FilterbankFile(fn, mode='readwrite')
    else:
        fil = filterbank.FilterbankFile(fn, mode='read')
    if args.inprof is not None:
        warnings.warn("Saved profiles already may be tuned to a particular " \
                        "DM, period and filterbank file (freq, nchans, " \
                        "tsamp, etc).")
        prof = load_profile(args.inprof)
    else:
        prof = make_profile(args.vonmises)
        prof = apply_dm(prof, args.period, args.dm, \
                        fil.foff, fil.frequencies, fil.tsamp)
        scale_profile(prof, args.scale_name, args.scale_cfgstrs, fil)
        if args.outprof is not None:
            save_profile(prof, args.outprof)

    outfn = args.outname % fil.header 
    print("Showing plot of profile to be injected...")
    plt.figure()

def main():
    fn = args[0]

    if fn.endswith(".fil"):
        # Filterbank file
        filetype = "filterbank"
        rawdatafile = filterbank.FilterbankFile(fn)
    elif fn.endswith(".fits"):
        # PSRFITS file
        filetype = "psrfits"
        rawdatafile = psrfits.PsrfitsFile(fn)
    else:
        raise ValueError("Cannot recognize data file type from "
                         "extension. (Only '.fits' and '.fil' "
                         "are supported.)")

    data, bins, nbins, start = waterfall(rawdatafile, options.start, \
                            options.duration, dm=options.dm,\
                            nbins=options.nbins, nsub=options.nsub,\
                            subdm=options.subdm, zerodm=options.zerodm, \
                            downsamp=options.downsamp, \
                            scaleindep=options.scaleindep, \
                            width_bins=options.width_bins, mask=options.mask, \