
    Write a function that validates whether a ride-sharing route identifier follows the system's standardized format, which requires all route segments to be lowercase letters connected by underscores. The function should return true if the identifier meets this format (like "north_central_route") and false otherwise.
    

    
import re

def text_lowercase_underscore(text):
    """
    Write a function that validates whether a ride-sharing route identifier follows the system's standardized format, which requires all route segments to be lowercase letters connected by underscores. The function should return true if the identifier meets this format (like "north_central_route") and false otherwise.
    

    """
import re

def text_lowercase_underscore(text):
    """
    Write a function that validates whether a ride-sharing route identifier follows the system's standardized format, which requires all route segments to be lowercase letters connected by underscores. The function should return true if the identifier meets this format (like "north_central_route") and false otherwise.
    

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