input: Write a python function to start a process within a virtual node using the HappyProcessStart class.
  assert isinstance(start_happy_process({"tag": "test_process", "command": "echo Hello"}), HappyProcessStart)
  assert start_happy_process({"tag": "test_process", "command": "echo Hello"}).tag == "test_process"
  assert start_happy_process({"tag": "test_process", "command": "echo Hello"}).command == "echo Hello"
output: def start_happy_process(process_details):
      class HappyProcessStart:
          def __init__(self, tag, command):
              self.tag = tag
              self.command = command
  
      return HappyProcessStart(process_details["tag"], process_details["command"])