There is one community led solution called pytonlib that I have found to send a transaction in Python. Please note that I have not tried it myself so I cannot in good faith recommend it, but the community members who work on it are quite active.

Install with:

pip install ton

Here is an example of how it is used to send a transaction.

from .init import client
from .wallet import wallet

# Viewing transactions
txs = await wallet.get_transactions()
in_msg = txs[0].in_msg
in_msg.source.account_address  # Sender
in_msg.destination.account_address  # Recipient
int(in_msg.amount)  # Amount in nanoTONs
client.from_nano(int(in_msg.value))  # Amount in TONs

# Sending transaction with 1 TON
await wallet.transfer('EQCl1Ug9ZT9ZfGyFH9l4q-bqaUy6kyOzVPmrk7bivmVKJRRZ', client.to_nano(1), comment='test')

# Send transaction with multiple outputs
await wallet.transfer(
    ('EQCl1Ug9ZT9ZfGyFH9l4q-bqaUy6kyOzVPmrk7bivmVKJRRZ', client.to_nano(1), 'test comment'),
    ('EQCl1Ug9ZT9ZfGyFH9l4q-bqaUy6kyOzVPmrk7bivmVKJRRZ', client.to_nano(0.5), 'test comment 2'),
    ('EQCl1Ug9ZT9ZfGyFH9l4q-bqaUy6kyOzVPmrk7bivmVKJRRZ', client.to_nano(1))
)

# Sending transaction with raw BOC data
from tvm_valuetypes import Cell
await wallet.transfer('EQCl1Ug9ZT9ZfGyFH9l4q-bqaUy6kyOzVPmrk7bivmVKJRRZ', client.to_nano(1), data=Cell().serialize_boc())