txt文件转为fasta文件

inf = "/media/disk/CJX/Genechi/chi_sum_test.txt"
outf= "/media/disk/CJX/Genechi/chi_sum_test2.txt"
def readwrite1(inf,outf):
f=open(inf,'r')
out=open(outf,'w')
next(f)   #不要第一行
for line in f.readlines():
list_line = line.strip().split()
x=list_line[0]+"\n"  #只要第一列
y="lalalaal\n"  #每一行前面添加的描述信息
out.writelines(y)   
out.writelines(x)
f.close()
out.close()
readwrite1(inf,outf)