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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 from_float_26(f):
 """Converts a float to a decimal number, exactly. Note that Decimal.from_float(0.1) is not the same as Decimal('0.1'). Since 0.1 is not exactly representable in binary floating point, the value is stored as the nearest representable value which is 0x1.999999999999ap-4. The exact equivalent of the value in decimal is 0.1000000000000000055511151231257827021181583404541015625. Decimal('0.1000000000000000055511151231257827021181583404541015625') Decimal('NaN') Decimal('Infinity') Decimal('-Infinity') Decimal('-0') """

    import math as _math
    from decimal import _dec_from_triple    # only available on Py2.6 and Py2.7 (not 3.3)

    if isinstance(f, (int, long)):        # handle integer inputs
        return Decimal(f)
    if _math.isinf(f) or _math.isnan(f):  # raises TypeError if not a float
        return Decimal(repr(f))
    if _math.copysign(1.0, f) == 1.0:
        sign = 0
    else:
        sign = 1
    n, d = abs(f).as_integer_ratio()
    # int.bit_length() method doesn't exist on Py2.6:
    def bit_length(d):
        if d != 0:
            return len(bin(abs(d))) - 2
        else:
            return 0
    k = bit_length(d) - 1
    result = _dec_from_triple(sign, str(n*5**k), -k)
    return result