pengzhangzhi

def renum_pdb_str(pdb_str, Ls=None, renum=True, offset=1):
    from string import ascii_uppercase, ascii_lowercase
    assert len(Ls) == 2
    Ls = [int(i) for i in Ls]
    alphabet_list = list(ascii_uppercase+ascii_lowercase)
    if Ls is not None:
        L_init = 0
        new_chain = {}
        for L,c in zip(Ls, alphabet_list):
            new_chain.update({i:c for i in range(L_init,L_init+L)})