def largest_negative_number(seq_seq):
    '\n    Returns the largest NEGATIVE number in the given sequence of\n    sequences of numbers.  Returns None if there are no negative numbers\n    in the sequence of sequences.\n\n    For example, if the given argument is:\n        [(30, -5, 8, -20),\n         (100, -2.6, 88, -40, -5),\n         (400, 500)\n        ]\n    then this function returns -2.6.\n\n    As another example, if the given argument is:\n      [(200, 2, 20), (500, 400)]\n    then this function returns None.\n\n    Preconditions:\n      :type seq_seq: (list, tuple)\n    and the given argument is a sequence of sequences,\n    where each subsequence contains only numbers.\n    '
    s = []
    for k in range(len(seq_seq)):
        s2 = seq_seq[k]
        if (s2 != []):
            s = (s + [max(s2)])
    return max(s)
Returns the largest NEGATIVE number in the given sequence of
sequences of numbers.  Returns None if there are no negative numbers
in the sequence of sequences.

For example, if the given argument is:
    [(30, -5, 8, -20),
     (100, -2.6, 88, -40, -5),
     (400, 500)
    ]
then this function returns -2.6.

As another example, if the given argument is:
  [(200, 2, 20), (500, 400)]
then this function returns None.

Preconditions:
  :type seq_seq: (list, tuple)
and the given argument is a sequence of sequences,
where each subsequence contains only numbers.
def largest_negative_number(seq_seq):
    '\n    Returns the largest NEGATIVE number in the given sequence of\n    sequences of numbers.  Returns None if there are no negative numbers\n    in the sequence of sequences.\n\n    For example, if the given argument is:\n        [(30, -5, 8, -20),\n         (100, -2.6, 88, -40, -5),\n         (400, 500)\n        ]\n    then this function returns -2.6.\n\n    As another example, if the given argument is:\n      [(200, 2, 20), (500, 400)]\n    then this function returns None.\n\n    Preconditions:\n      :type seq_seq: (list, tuple)\n    and the given argument is a sequence of sequences,\n    where each subsequence contains only numbers.\n    '
    s = []
    for k in range(len(seq_seq)):
        s2 = seq_seq[k]
        if (s2 != []):
            s = (s + [max(s2)])
    return max(s)