I would like to ask how to call my python methods in daml?

Questions
1

I would like to ask how to call my python methods in daml? I wanted to implement keccak_256 encryption, but only found sha256 in daml.

2

You cannot call into python code (or any other language) from within Daml.

If you need to communicate with outside services, you can create a request contract in your Daml code and then compute the response on the client side. Something like this:

template Keccak_256Request
  with
    p : Party
    textToHash : Text
  where
    signatory p

    choice Respond : ()
      with
        hash : Text
      controller p
      do -- fill in how you want to continue here
         pure ()

test = script do
  p <- allocateParty "p"
  -- Create the request in your Daml code
  cid <- submit p $ createCmd (Keccak_256Request p "text to hash")
  -- compute the hash in your python code
  -- submit the exercise from your python code with the right hash
  submit p $ exerciseCmd cid (Respond "fill in the hash here")