Add documentation

[harshraj22]

rl_lab/lab2/data_loader/environments.py

Line 12 in e116f3c

def __init__(self, arm_initializer: Callable, num_arms: int=3, total_timesteps: int=1000) -> None:

Add documentation about arm_initializer etc. It is not very clear what it is, and what it does just by type hints.