code: async def generate_psk(self, security_key):
          
          if not self._psk:
              PatchedDTLSSecurityStore.IDENTITY = 'Client_identity'.encode(
                  'utf-8')
              PatchedDTLSSecurityStore.KEY = security_key.encode('utf-8')
  
              command = Gateway().generate_psk(self._psk_id)
              self._psk = await self.request(command)
  
              PatchedDTLSSecurityStore.IDENTITY = self._psk_id.encode('utf-8')
              PatchedDTLSSecurityStore.KEY = self._psk.encode('utf-8')
  
              # aiocoap has now cached our psk, so it must be reset.
              # We also no longer need the protocol, so this will clean that up.
              await self._reset_protocol()
  
          return self._psk
docs: Generate and set a psk from the security key.