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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 IEEEContext(bitwidth):
 """ Return IEEE 754-2008 context for a given bit width. The IEEE 754 standard specifies binary interchange formats with bitwidths 16, 32, 64, 128, and all multiples of 32 greater than 128. This function returns the context corresponding to the interchange format for the given bitwidth. See section 3.6 of IEEE 754-2008 or the bigfloat source for more details. """

    try:
        precision = {16: 11, 32: 24, 64: 53, 128: 113}[bitwidth]
    except KeyError:
        if not (bitwidth >= 128 and bitwidth % 32 == 0):
            raise ValueError("nonstandard bitwidth: bitwidth should be "
                             "16, 32, 64, 128, or k*32 for some k >= 4")
        # The formula for the precision involves rounding 4*log2(width) to the
        # nearest integer. We have:
        #
        #   round(4*log2(width)) == round(log2(width**8)/2)
        #                        == floor((log2(width**8) + 1)/2)
        #                        == (width**8).bit_length() // 2
        #
        # (Note that 8*log2(width) can never be an odd integer, so we
        # don't care which way half-way cases round in the 'round'
        # operation.)
        precision = bitwidth - _bit_length(bitwidth ** 8) // 2 + 13

    emax = 1 << bitwidth - precision - 1
    return Context(
        precision=precision,
        emin=4 - emax - precision,
        emax=emax,
        subnormalize=True,
    )