python从gbff文件中直接提取cds序列

import re
FILE_PATH = './input.gb'
OUT_FILE_PATH = './output.fasta'
d = {}
g = {}
tem = []
def con_spl(list_,n = 2):
    return [list_[i:i + n] for i in range(0, len(list_), n)]
with open (FILE_PATH,'r')as f:
    while True:
        text_line = f.readline().strip('\t').split()
        if text_line:
            if text_line[0] == 'DEFINITION':
                c = ' '.join(i for i in text_line[2:])
                d[c] = []
                g[c] = []
                print (text_line)
            elif text_line[0] == 'CDS':
                cds = re.findall(r"\d+\d*?",text_line[1])
                if len(cds) == 2:
                    d[c].append(cds)
                else:
                    for i in con_spl(cds):
                        d[c].append(i)
            elif text_line[0] == 'ORIGIN':
                while text_line[0] != '//':
                    for i in text_line[1:]:
                        tem.append(i)
                    text_line = f.readline().strip('\t').split()
                e = ''.join(i for i in tem)
                g[c].append(e)
            else:
                pass
        elif f.readline().strip('\t').split():
            continue
        else:
            break
with open (OUT_FILE_PATH,'w')as f:
    for i,o in d.items():
        G = ''.join(g[I])
        p = ''
        for u in o:
            u1 = int(u[0])
            u2 = int(u[1])+1
            p += G[u1:u2]
        print ('>',i,sep='',file=f)
        print (p,file=f)