When squirrels get together for a party, they like to have cigars. A squirrel party is successful when the number of cigars is between 40 and 60, inclusive. Unless it is the weekend, in which case there is no upper bound on the number of cigars. Return true if the party with the given values is successful, or false otherwise.
Here is a Python function that implements the logic you described:
```
def squirrel_party(is_weekend, num_cigars):
    if is_weekend:
        return num_cigars >= 40
    else:
        return 40 <= num_cigars <= 60
```
Here's an explanation of how the function works:

* If it's the weekend (`is_weekend` is `True`), the only requirement is that there are at least 40 cigars. So, the function returns `True` if `num_cigars` is 40 or more.
* If it's not the weekend (`is_weekend` is `False`), the function checks if the number of cigars is between 40 and 60, inclusive. This is done using the chained comparison `40 <= num_cigars <= 60`. If this condition is true, the function returns `True`. Otherwise, it returns `False`.

You can test this function with different inputs to see how it behaves. For example:
```
print(squirrel_party(True, 30))  # False (not enough cigars on the weekend)
print(squirrel_party(True, 50))  # True (enough cigars on the weekend)
print(squirrel_party(False, 30))  # False (not enough cigars on a weekday)
print(squirrel_party(False, 50))  # True (enough cigars on a weekday)
print(squirrel_party(False, 70))
True