How to use the pygtftk.utils.chrom_info_as_dict function in pygtftk

def shift(inputfile=None,
          outputfile=None,
          shift_value=None,
          chrom_info=None,
          stranded=False,
          allow_outside=False):
    """Shift coordinates in 3' or 5' direction.
    """

    gtf = GTF(inputfile, check_ensembl_format=False)

    chrom_list_gtf = gtf.get_chroms(nr=True)
    chrom_info = chrom_info_as_dict(chrom_info)

    for chr in chrom_list_gtf:
        if chr not in chrom_info:
            raise GTFtkError("Chromosome " + chr + " was not found in chrom-info file.")

    for i in gtf:
        size = i.end - i.start + 1
        if not stranded:
            new_start = i.start + shift_value
            new_end = i.end + shift_value
        else:
            if i.strand == "-":
                new_start = i.start - shift_value
                new_end = i.end - shift_value
            else:
                new_start = i.start + shift_value

go_id="GO:0003700",
                      species="hsapiens",
                      upstream=1000,
                      downstream=1000,
                      chrom_info=None,
                      distal=1000000,
                      mode='basal_plus_extension',
                      http_proxy=None,
                      https_proxy=None):
    """ Given a GTF and a GO term, attempt compute labeled regions using GREAT 'association rule'. """

    # -------------------------------------------------------------------------
    # chrom_len will store the chromosome sizes.
    # -------------------------------------------------------------------------

    chrom_len = chrom_info_as_dict(chrom_info)

    # -------------------------------------------------------------------------
    # Read the GTF
    # -------------------------------------------------------------------------

    gtf = GTF(inputfile, check_ensembl_format=False)

    # -------------------------------------------------------------------------
    # Get the TSSs -- Extend them by upstream/dowstream
    # -------------------------------------------------------------------------

    message("Defining basal regulatory domains.", type="INFO")
    basal_reg_bed = gtf.get_tss(name=['gene_id', 'gene_name']).slop(s=True,
                                                                    l=upstream,
                                                                    r=downstream,
                                                                    g=chrom_info.name).sort()

"provide --more-keys or --more-bed.",
                        type="ERROR")
    else:
        if inputfile is None:
            message("Please provide a GTF.",
                    type="ERROR")

        if chrom_info is None:
            message("Please provide a chromInfo file (--chrom-info)",
                    type="ERROR")

    # -------------------------------------------------------------------------
    # chrom_len will store the chromosome sizes.
    # -------------------------------------------------------------------------

    chrom_len = chrom_info_as_dict(chrom_info)

    # -------------------------------------------------------------------------
    # Load the peak file as pybedtools.BedTool object
    # -------------------------------------------------------------------------

    peak_file = pybedtools.BedTool(peak_file.name)

    # -------------------------------------------------------------------------
    # Check chromosomes for peaks are defined in the chrom-info file
    # Depending on force_chrom_peak, peaks undefined in peak_file may
    # be silently removed.
    # -------------------------------------------------------------------------

    peak_chrom_list = set()

    for i in pybedtools.BedTool(peak_file):

tmp_file_chr = make_tmp_file(prefix='chromsize', suffix='.txt')
            for chrom, size in chr_size.items():
                tmp_file_chr.write(chrom + "\t" + str(size[1]) + "\n")
            tmp_file_chr.close()
            values = open(tmp_file_chr.name, 'r')
        elif values == 'simple':
            chr_size = {'chr1': 300, 'chr2': 600}
            tmp_file_chr = make_tmp_file(prefix='chromsize', suffix='.txt')
            for chrom, size in chr_size.items():
                tmp_file_chr.write(chrom + "\t" + str(size) + "\n")
            tmp_file_chr.close()
            values = open(tmp_file_chr.name, 'r')
        else:
            check_file_or_dir_exists(values)
            values = open(values, "r")
            chrom_info_as_dict(values)

        # Add the attribute
        setattr(namespace, self.dest, values)