$16.$ Implement isnetid

Read the specification of the function isnetid in the module funcs. Netids are a way that we identify students and employees at Cornell. Implement this function according to its specification. Once again, you may not use introcs or a loop. You must use the methods built into the string data type.

When you have implemented the function, test your answer with the test script. You should now pass all tests.

def isnetid$($s$)$:

$"""$

Returns True if s is a valid Cornell netid.

Cornell network ids consist of $2$ or $3$ lower$-$case initials followed by a

sequence of digits.

Examples:

isnetid$(\text{'}$wmw$2\text{'})$ returns True

isnetid$(\text{'}2$wmw$\text{'})$ returns False

isnetid$(\text{'}$ww$2345\text{'})$ returns True

isnetid$(\text{'}$w$2345\text{'})$ returns False

isnetid$(\text{'}$WW$345\text{'})$ returns False

Parameter s: the string to check

Precondition: s is a string

$"""$