Read from the messages table

Read from messages table, if to matches read_msg_to, decrypt a message and then delete it.
def read_and_delete_msg(private_key_file, read_msg_to):
    privkey_bytes = read_privkey_file(private_key_file)
    privkey = keys.UmbralPrivateKey.from_bytes(privkey_bytes)
    
    payload = '{"scope":"' + DEFAULT_ACCOUNT + '","code":"' + DEFAULT_ACCOUNT + '","table": "' + DEFAULT_TABLE+ '", "json":"true"}'
    response = requests.request("POST", DEFAULT_URL, data=payload)   
    
    found = False
    for msg in response.json()['rows']:
        if msg['to'] == read_msg_to:
            ciphertext = msg['ciphertext']
            capsule = msg['capsule']
            msg_id = msg['msg_id']
            found = True
            break

    if found:        
        capule = pre.Capsule.from_bytes(bytes.fromhex(capsule), privkey.params)
        cleartext = pre.decrypt(
                          ciphertext = bytes.fromhex(ciphertext),
                          capsule = capule,
                          decrypting_key = privkey)
        print('Cleartext: {}'.format(cleartext))
        
        print('Deleting msg_id: {}'.format(msg_id))
        data = '{"to":"' + read_msg_to + '", "msg_id":"' + str(msg_id) + '"}'
        subprocess.call(['cleos', 'push', 'action', DEFAULT_ACCOUNT, 'deletemsg', data , '-p', read_msg_to])