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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 _integerValue_to_int(value_str):
 """ Convert a value string that conforms to DSP0004 `integerValue`, into the corresponding integer and return it. The returned value has Python type `int`, or in Python 2, type `long` if needed. Note that DSP0207 and DSP0004 only allow US-ASCII decimal digits. However, the Python `int()` function supports all Unicode decimal digits (e.g. US-ASCII digits, ARABIC-INDIC digits, superscripts, subscripts) and raises `ValueError` for non-decimal digits (e.g. Kharoshthi digits). Therefore, the match patterns explicitly check for US-ASCII digits, and the `int()` function should never raise `ValueError`. Returns `None` if the value string does not conform to `integerValue`. """

    m = BINARY_VALUE.match(value_str)
    if m:
        value = int(m.group(1), 2)
    elif OCTAL_VALUE.match(value_str):
        value = int(value_str, 8)
    elif DECIMAL_VALUE.match(value_str):
        value = int(value_str)
    elif HEX_VALUE.match(value_str):
        value = int(value_str, 16)
    else:
        value = None
    return value