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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 get_dict_from_buffer(buf, keys=['DISTNAME', 'MAJOR', 'MINOR', 'PATCHLEVEL', 'PYTHON', 'MIN_PYTHON_MAJOR', 'MIN_PYTHON_MINOR', 'MIN_NUMPY_MAJOR', 'MIN_NUMPY_MINOR']):
 """ Parses a string buffer for key-val pairs for the supplied keys. Returns: Python dictionary with all the keys (all keys in buffer if None is passed for keys) with the values being a list corresponding to each key. Note: Return dict will contain all keys supplied (if not None). If any key was not found in the buffer, then the value for that key will be [] such that dict[key] does not produce a KeyError. Slightly modified from: "http://stackoverflow.com/questions/5323703/regex-how-to-"\ "match-sequence-of-key-value-pairs-at-end-of-string """



    pairs = dict()
    if keys is None:
        keys = "\S+"
        regex = re.compile(r'''
        \n            # all key-value pairs are on separate lines
        \s*           # there might be some leading spaces
        (             # start group to return
        (?:{0}\s*)    # placeholder for tags to detect '\S+' == all
        \s*:*=\s*     # optional spaces, optional colon, = , optional spaces
        .*            # the value
        )             # end group to return
        '''.format(keys), re.VERBOSE)
        validate = False
    else:
        keys = [k.strip() for k in keys]
        regex = re.compile(r'''
        \n            # all key-value pairs are on separate lines
        \s*           # there might be some leading spaces
        (             # start group to return
        (?:{0}\s*)    # placeholder for tags to detect '\S+' == all
        \s*:*=\s*     # optional spaces, optional colon, = , optional spaces
        .*            # the value
        )             # end group to return
        '''.format('|'.join(keys)), re.VERBOSE)
        validate = True
        for k in keys:
            pairs[k] = []

    matches = regex.findall(buf)
    for match in matches:
        key, val = match.split('=', 1)

        # remove colon and leading/trailing whitespace from key
        key = (strip_line(key, ':')).strip()

        # remove newline and leading/trailing whitespace from value
        val = (strip_line(val)).strip()
        if validate and key not in keys:
            msg = "regex produced incorrect match. regex pattern = {0} "\
                  "claims key = [{1}] while original set of search keys "\
                  "= {2}".format(regex.pattern, key, '|'.join(keys))
            raise AssertionError(msg)
        pairs.setdefault(key, []).append(val)

    return pairs