StepType for a trajectory with only two steps

[chz816]

Hi team, thank you for this great package! I have a question related to the value of StepType when we have a relatively short trajectory. So based on my understanding, the StepType equals to FIRST for the first state and equals to LAST for the last state. Otherwise it should take the value MID. My questions is for a short trajectory with only two steps {step1, step2}, when we define the step_type and next_step_type, should it be:

• step 1: step_type=FIRST, next_step_type=LAST OR
• step 1: step_type=FIRST, next_step_type=MID?

Similar question for step 2. Any help is appreciated. Thank you!