Nothing happens when I run code for coding challenge

Question

I'm in the first coding project for the "Python for Data Science" course (the basketball players one), and when I run my code, nothing happens. The Results tab doesn't show anything except "Test Case 1" which is hidden. I don't see any output or even errors.
For reference, this is my code:
players = [180, 172, 178, 185, 190, 195, 192, 200, 210, 190]
mean = sum(players)/len(players)
diffs = [(p-mean)**2 for p in players]
variance = sum(diffs)/len(diffs)
std = variance**-2
players_in_std = [p for p in players if (mean-std)<=p<=(mean+std)]
print(len(players_in_std))

Answer 1

# Hi! Debug your code in playgrund! Print all partial results! Look at them! Find the errors!
# - - - - - - - - - - - - - - - - - -
players = [180, 172, 178, 185, 190, 195, 192, 200, 210, 190]
mean = sum(players) / len(players)
print(f"{mean = }")
diffs = [(p - mean) ** 2 for p in players]
print(f"\n{diffs = }\n")
variance = sum(diffs) / len(diffs)
# std = variance ** (-2) # Something wrong here!
std = variance ** (1/2) # Try this!
print(f"{variance = }\n{std = }\n{mean - std = }\n{mean + std = }")
players_in_std = [p for p in players if (mean - std) <= p <= (mean + std)]
print(f"\n{players = }")
print(f"{players_in_std = }")
print(f"{len(players_in_std) = }")
# - - - - - - - - - - - - - - - - - -
# Put the code in playground and start to work! Copy the hole code in this message to playground!
https://code.sololearn.com/cG7ijtqWp4t5/?ref=app