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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 _vcf_alt(base, other_chr, other_pos, isrc, is_first):
 """Create ALT allele line in VCF 4.1 format associating with other paired end. """

    if is_first:
        pipe = "[" if isrc else "]"
        out_str = "{base}{pipe}{chr}:{pos}{pipe}"
    else:
        pipe = "]" if isrc else "["
        out_str = "{pipe}{chr}:{pos}{pipe}{base}"
    return out_str.format(pipe=pipe, chr=other_chr, pos=other_pos + 1,
                          base=base)