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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 write_vcf(path, callset, rename=None, number=None, description=None, fill=None, write_header=True):
 """Preliminary support for writing a VCF file. Currently does not support sample data. Needs further work."""


    names, callset = normalize_callset(callset)

    with open(path, 'w') as vcf_file:
        if write_header:
            write_vcf_header(vcf_file, names, callset=callset, rename=rename,
                             number=number, description=description)
        write_vcf_data(vcf_file, names, callset=callset, rename=rename, fill=fill)