def seqs_dic_count_chars(seqs_dic):
    """
    Given a dictionary with sequences, count how many times each character
    appears.

    >>> seqs_dic = {'s1': 'ABCC', 's2': 'ABCD'}
    >>> seqs_dic_count_chars(seqs_dic)
    {'A': 2, 'B': 2, 'C': 3, 'D': 1}

    """
    assert seqs_dic, "given seqs_dic empty"
    cc_dic = {}
    for seq_id in seqs_dic:
        seq = seqs_dic[seq_id]
        for c in seq:
            if c in cc_dic:
                cc_dic[c] += 1
            else:
                cc_dic[c] = 1
    assert cc_dic, "cc_dic empty"
    return cc_dic