
Three Words

Let's teach the Robots to distinguish words and numbers.
You are given a string with words and numbers separated by whitespaces (one space). The words contain only letters. You should check if the string contains three words in succession. For example, the string "start 5 one two three 7 end" contains three words in succession.
Input: A string (str) with words.
Output: Logic value (bool).
Examples:
assert checkio("Hello World hello") == True assert checkio("He is 123 man") == False assert checkio("1 2 3 4") == False assert checkio("bla bla bla bla") == True
How it is used: This teaches you how to work with strings and introduces some useful functions.
Precondition:
The input contains words and/or numbers. There are no mixed words (letters and digits combined).
0 < len(words) < 100