eth_sendTransaction does not exist/is not available after calling mint_liquidity method.

[MohsenRazavi]

Hello friends !
I'm having trouble interacting with the uniswap liquidity pool using uniswap-python. this is my code :

from web3 import Web3
from uniswap import Uniswap
from web3.middleware import geth_poa_middleware

from contracts import USDT, WMATIC

WALLET_ADDRESS = '...'
PK = '...'
VERSION = 3
PROVIDER = "https://polygon-mainnet.infura.io/v3/" +'INFURA_KEY'

AMOUNT = 0.5

w3 = Web3(Web3.HTTPProvider(PROVIDER))
uniswap = Uniswap(address=WALLET_ADDRESS, private_key=PK, version=VERSION, provider=PROVIDER)
uniswap.w3.middleware_onion.inject(geth_poa_middleware, layer=0)

pool = uniswap.get_pool_instance(token_0=WMATIC.address, token_1=USDT.address)

amount_0 = w3.to_wei(AMOUNT, WMATIC.get_decimal_unit())
amount_1 = uniswap.get_price_input(WMATIC.address, USDT.address, qty=amount_0)

nft = uniswap.mint_liquidity(pool=pool, amount_0=amount_0, amount_1=amount_1, tick_lower=0, tick_upper=887220)

print(nft)

and The error is :
web3.exceptions.MethodNavailable: {'code': -32601, 'message': 'eth_sendTransaction method does not exist/not available'}
I tried other RPCs and other pairs, but the problem still exists.