No output when trying to obtain protein sequence from PDB file

2 hours ago by

I am trying to obtain the sequence from the PDB file, but no output is given when I run the following code :

from Bio import SeqIO
from Bio.PDB import *
import numpy as np

    with open("1a9l.pdb", "r") as handle:
        for record in SeqIO.parse(handle, "pdb-atom"):
            print(record.seq)