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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 _convert_hashes(values):
 """Convert Pipfile.lock hash lines into InstallRequirement option format. The option format uses a str-list mapping. Keys are hash algorithms, and the list contains all values of that algorithm. """

    hashes = {}
    if not values:
        return hashes
    for value in values:
        try:
            name, value = value.split(":", 1)
        except ValueError:
            name = "sha256"
        if name not in hashes:
            hashes[name] = []
        hashes[name].append(value)
    return hashes