can't get example code from documentation to run

[pthornton614]

Installed the library, was able to run the single player one liner. Tried making a py file with the example code, and getting the error below.

Example code, ive named testGym.py:
GNU nano 4.8 testGym.py
from nes_py.wrappers import JoypadSpace
import gym_tetris
from gym_tetris.actions import MOVEMENT

env = gym_tetris.make('Tetris-v0')
env = JoypadSpace(env, MOVEMENT)

done = True
for step in range(5000):
if done:
state = env.reset()
state, reward, done, info = env.step(env.action_space.sample())
env.render()

env.close()

____________________________________________________-
error i receive:

(base) peter@peter-VirtualBox:~/TetrisAIProject$ python testGym.py
Traceback (most recent call last):
File "/home/peter/conda3/lib/python3.7/site-packages/gym/envs/registration.py", line 121, in spec
return self.env_specs[id]
KeyError: 'Tetris-v0'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
File "testGym.py", line 5, in
env = gym_tetris.make('Tetris-v0')
File "/home/peter/conda3/lib/python3.7/site-packages/gym/envs/registration.py", line 145, in make
return registry.make(id, **kwargs)
File "/home/peter/conda3/lib/python3.7/site-packages/gym/envs/registration.py", line 89, in make
spec = self.spec(path)
File "/home/peter/conda3/lib/python3.7/site-packages/gym/envs/registration.py", line 131, in spec
raise error.UnregisteredEnv('No registered env with id: {}'.format(id))
gym.error.UnregisteredEnv: No registered env with id: Tetris-v0
(base) peter@peter-VirtualBox:~/TetrisAIProject$ testGym.py
testGym.py: command not found