How to use the cjio.cityjson.reader function in cjio

def processor(cm):
        print_cmd_status('Merging files') 
        lsCMs = []
        g = glob.glob(filepattern)
        for i in g:
            try:
                f = click.open_file(i, mode='r')
                lsCMs.append(cityjson.reader(f))
            except ValueError as e:
                raise click.ClickException('%s: "%s".' % (e, input))
            except IOError as e:
                raise click.ClickException('Invalid file: "%s".' % (input))
        if len(lsCMs) == 0:
            click.echo("WARNING: No files to merge.")
        else:
            for i in lsCMs:
                click.echo("\t%s" % i)
            cm.merge(lsCMs)
        return cm
    return processor

f = click.open_file(input, mode='r')
        extension = os.path.splitext(input)[1].lower()
        if extension not in extensions:
            raise IOError("File type not supported (only .json, .off, and .poly).")
        #-- OFF file
        if (extension == '.off'):
            print_cmd_status("Converting %s to CityJSON" % (input))
            cm = cityjson.off2cj(f)
        #-- POLY file
        elif (extension == '.poly'):
            print_cmd_status("Converting %s to CityJSON" % (input))
            cm = cityjson.poly2cj(f)            
        #-- CityJSON file
        else: 
            print_cmd_status("Parsing %s" % (input))
            cm = cityjson.reader(file=f, ignore_duplicate_keys=ignore_duplicate_keys)
            if (cm.get_version() not in cityjson.CITYJSON_VERSIONS_SUPPORTED):
                allv = ""
                for v in cityjson.CITYJSON_VERSIONS_SUPPORTED:
                    allv = allv + v + "/"
                str = "CityJSON version %s not supported (only versions: %s), not every operators will work.\nPerhaps it's time to upgrade cjio? 'pip install cjio -U'" % (cm.get_version(), allv)
                raise click.ClickException(str)
            elif (cm.get_version() != cityjson.CITYJSON_VERSIONS_SUPPORTED[-1]):
                str = "v%s is not the latest version, and not everything will work.\n" % cm.get_version()
                str += "Upgrade the file with 'upgrade_version' command: 'cjio input.json upgrade_version save out.json'" 
                click.echo(click.style(str, fg='red'))
            
    except ValueError as e:
        raise click.ClickException('%s: "%s".' % (e, input))
    except IOError as e:
        raise click.ClickException('Invalid file: "%s".\n%s' % (input, e))
    for processor in processors: