[Bug Report] Equals Method of gym.spaces.Tuple does not Work Correclty

[maximilianreimer]

Describe the bug
Equals methods of gym.spaces.Tuple does state that two Space instances do not equal if they contain the same Space but instance a was initialized using a list of subspaces and b using a tuple of instances.

Suggestion:

1. Convert lists to a tuples in __init__
2. Raise error if list is passed to __init__
3. Change __eq__

Code example

from gym.spaces import Tuple
t1 = Tuple(tuple())
t2 = Tuple(list())

t1 == t2

System Info
Describe the characteristic of your environment:

• pip install gym==0.15.3
• openSUSE Leap 15.3
• Python version: 3.6.13

[MathieuTuli]

opinion: This is a valid bug, and I think suggestion #1 makes most sense. Internally, gym.spaces.Tuple already performs promotion to tuples (See here) to account for the very issue that this issue raises (passing a list instead of a tuple). Functionally, this class should behave as a Tuple, so having an internal list representation is flawed, and should be converted to a tuple.

The fix is straightforward, have a PR on standby pending no disagreements with the above