import re


def seqs_dic_count_lc_nts(seqs_dic):
    """
    Count number of lowercase nucleotides in sequences stored in sequence
    dictionary.

    >>> seqs_dic = {'seq1': "gtACGTac", 'seq2': 'cgtACacg'}
    >>> seqs_dic_count_lc_nts(seqs_dic)
    10
    >>> seqs_dic = {'seq1': "ACGT", 'seq2': 'ACGTAC'}
    >>> seqs_dic_count_lc_nts(seqs_dic)
    0

    """
    assert seqs_dic, "Given sequence dictionary empty"
    c_uc = 0
    for seq_id in seqs_dic:
        c_uc += len(re.findall(r'[a-z]', seqs_dic[seq_id]))
    return c_uc