
    Write a function to validate delivery route identifiers in the transportation system by checking if they follow the standardized naming convention of lowercase letters connected by underscores. The function should return true for valid route identifiers like "north_route_alternate" and false for any identifiers that deviate from this format.
    

    
import re

def text_lowercase_underscore(text):
    """
    Write a function to validate delivery route identifiers in the transportation system by checking if they follow the standardized naming convention of lowercase letters connected by underscores. The function should return true for valid route identifiers like "north_route_alternate" and false for any identifiers that deviate from this format.
    

    """
import re

def text_lowercase_underscore(text):
    """
    Write a function to validate delivery route identifiers in the transportation system by checking if they follow the standardized naming convention of lowercase letters connected by underscores. The function should return true for valid route identifiers like "north_route_alternate" and false for any identifiers that deviate from this format.
    

    """
    patterns = '^[a-z]+_[a-z]+$'
    if re.search(patterns, text):
        return True
    else:
        return False