Valid Name

For this exercise, keep in mind the following two terms (mutually exclusive):

1. initials = 1 character
2. words = 2+ characters (no dots allowed)

A valid name is a name written in one of the following ways:

• H. Wells
• H. G. Wells
• Herbert G. Wells
• Herbert George Wells

The following names are invalid:

• Herbert or Wells (single names not allowed)
• H Wells or H. G Wells (initials must end with dot)
• h. Wells or H. wells or h. g. Wells (incorrect capitalization)
• H. George Wells (middle name expanded, while first still left as initial)
• H. G. W. (last name is not a word)
• Herb. G. W. (dot only allowed after initial, not word)

Rules

1. Both initials and words must be capitalized.
2. Initials must end with a dot.
3. A name must be either 2 or 3 words long (depending on whether a middle name exists).
4. If the name is 3 words long, you can expand the first and middle name or expand the first name only. You cannot keep the first name as an initial and expand the middle name only.
5. The last name must be a word (not an initial).

Your task is to write a function that determines whether a name is valid or not. Return True if the name is valid, False otherwise.

Examples

valid_name("H. Wells") ➞ True

valid_name("H. G. Wells") ➞ True

valid_name("Herbert G. Wells") ➞ True

valid_name("Herbert") ➞ False
# Must be 2 or 3 words

valid_name("h. Wells") ➞ False
# Incorrect capitalization

valid_name("H Wells") ➞ False
# Missing dot after initial

valid_name("H. George Wells") ➞ False
# Cannot have: initial first name + word middle name

valid_name("H. George W.") ➞ False
# Last name cannot be initial

Notes

N/A