Hi Ilya and forum folks... I encountered similar issue on lab 4.1 but I could not find the simple_chaincode under the chaincode folder as per the solve posted on this link: https://forum.linuxfoundation.org/discussion/857440/error-while-installing-simplechaincode-on-peer
Kindly advise. Thank you in advance!

Here is all folders I have:

~/src/github.com/hyperledger/fabric-samples/chaincode# ls -alrt
total 36
drwxr-xr-x  3 root root 4096 Nov 30 15:36 abac
drwxr-xr-x  3 root root 4096 Nov 30 15:36 marbles02_private
drwxr-xr-x  5 root root 4096 Nov 30 15:36 chaincode_example02
drwxr-xr-x  2 root root 4096 Nov 30 15:36 sacc
drwxr-xr-x  4 root root 4096 Nov 30 15:36 marbles02
drwxr-xr-x  7 root root 4096 Nov 30 15:36 fabcar
drwxr-xr-x 17 root root 4096 Nov 30 15:37 ..
drwxr-xr-x  3 root root 4096 Nov 30 15:55 hyperledger
drwxr-xr-x  9 root root 4096 Nov 30 15:55 .

Here is error I got:

~/go/src/github.com/hyperledger/fabric-samples/basic-network# docker exec -it cli bash
/opt/gopath/src/github.com/hyperledger/fabric/peer# echo $CORE_PEER_ADDRESS $CORE_PEERLOCALMSPID $CORE_PEER_MSPCONFIGPATH
peer0.org1.example.com:7051 /opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/peerOrganizations/org1.example.com/users/Admin@org1.example.com/msp
opt/gopath/src/github.com/hyperledger/fabric/peer# peer chaincode install -n simple_cc -v 1.0 -p github.com/simple_chaincode -l golang
2020-12-01 00:31:21.483 UTC [chaincodeCmd] checkChaincodeCmdParams -> INFO 001 Using default escc
2020-12-01 00:31:21.483 UTC [chaincodeCmd] checkChaincodeCmdParams -> INFO 002 Using default vscc
Error: error getting chaincode code simple_cc: path to chaincode does not exist: /opt/gopath/src/github.com/simple_chaincode