# Profile: Python basics. These checks run in the normal interpreter.
import math


def mean_minutes(values):
    """Return the arithmetic mean; empty input is an error."""
    if not values:
        raise ValueError("at least one value is required")
    return sum(values) / len(values)


assert math.isclose(mean_minutes([10, 20, 30]), 20.0)
assert math.isclose(mean_minutes([12]), 12.0)
assert math.isclose(mean_minutes([0, 0]), 0.0)
try:
    mean_minutes([])
except ValueError:
    print("Empty-input check passed")
else:
    raise AssertionError("empty input should raise ValueError")
print("Three numeric checks passed")