Python and Scapy - Get list of all TCP destination ports occuring in a pcap

gettcpports.py

from scapy.all import *
from natsort import natsorted

packets = rdpcap('in.pcap')
result = []
for packet in packets:
    if TCP in packet:
        tcpport = str(packet[TCP].dport)
        if tcpport not in result:
            result.append(tcpport)
result = natsorted(result)
print('\n'.join(result))