
    Write a function to validate whether a delivery route configuration contains a primary hub followed by either two or three connected distribution points in the logistics chain. The route configuration uses 'a' to denote a primary hub and 'b' to denote distribution points, and only routes with one hub connected to exactly two or three distribution points are considered valid.
    

    
import re

def text_match_two_three(text):
    """
    Write a function to validate whether a delivery route configuration contains a primary hub followed by either two or three connected distribution points in the logistics chain. The route configuration uses 'a' to denote a primary hub and 'b' to denote distribution points, and only routes with one hub connected to exactly two or three distribution points are considered valid.
    

    """
import re

def text_match_two_three(text):
    """
    Write a function to validate whether a delivery route configuration contains a primary hub followed by either two or three connected distribution points in the logistics chain. The route configuration uses 'a' to denote a primary hub and 'b' to denote distribution points, and only routes with one hub connected to exactly two or three distribution points are considered valid.
    

    """
    patterns = 'ab{2,3}'
    if re.search(patterns, text):
        return True
    else:
        return False