inheritted method from PyEnvironment causes error because underscore at start of function name

Question

i get the error below.

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
Input In [3], in <cell line: 30>()
     27     def observation_spec(self):
     28         return self._observation_spec
---> 30 env = connect4_env(4)

TypeError: Can't instantiate abstract class connect4_env with abstract methods _reset, _step

i never actually make the function _reset so it must be coming from py_environment.PyEnvironment

code below

from tf_agents.environments import py_environment
from tf_agents.environments import tf_environment
from tf_agents.environments import tf_py_environment
from tf_agents.environments import utils
from tf_agents.specs import array_spec
from tf_agents.environments import wrappers
from tf_agents.environments import suite_gym
from tf_agents.trajectories import time_step as ts

class connect4_env(py_environment.PyEnvironment):
    
    def __init__(self , num_slots):
    
        self._action_spec = array_spec.BoundedArraySpec(
            shape=(), dtype=np.int32, minimum=0, maximum=num_slots-1, name='play')

        self._observation_spec = array_spec.BoundedArraySpec(
            shape=(1,num_slots), dtype=np.int32, minimum=0, maximum=1, name='board')

        self._state = [0 for num in num_slots]
        self._episode_ended = False
        
    def action_spec(self):
        return self._action_spec
    
    def observation_spec(self):
        return self._observation_spec

env = connect4_env(4)

how can i fix this?

why is this happening? if it is from py_environment.PyEnvironment isnt it built in? why would a built in function have a name that breaks everything?

###################

extra info below

im using anaconda

im using tf_agents version 0.13.0

im following this tutorial (but slightly different) https://towardsdatascience.com/creating-a-custom-environment-for-tensorflow-agent-tic-tac-toe-example-b66902f73059

I believe the problem is as stated in the title but i dont know for sure

###############################

update

i have made these changes

from tf_agents.environments import py_environment , _reset, _step


class connect4_env(py_environment.PyEnvironment):
    @_reset 
    @_step
    def __init__(self , num_slots):
    

because i belive i need to import _reset from tf_agents.environments and the use @_reset when creating my class but now get this error.

ImportError: cannot import name '_reset' from 'tf_agents.environments' (C:\Users\tgmjack\anaconda3\lib\site-packages\tf_agents\environments\__init__.py)

ill keep looking

i dont seem to be able to import the abstract functions though

Answer 1

Please read about abstract classes here or look it up on Google.

You need to implement all the abstract methods defined in py_environment.PyEnvironment in your subclass that inherits from it.