
    Write a function to validate if a customer's financial behavior identifier follows the bank's standardized format, which requires sequences of lowercase letters connected by underscores. The function should return true if the identifier matches this pattern (like payment_history_good) and false for any other format.
    

    
import re

def text_lowercase_underscore(text):
    """
    Write a function to validate if a customer's financial behavior identifier follows the bank's standardized format, which requires sequences of lowercase letters connected by underscores. The function should return true if the identifier matches this pattern (like payment_history_good) and false for any other format.
    

    """
import re

def text_lowercase_underscore(text):
    """
    Write a function to validate if a customer's financial behavior identifier follows the bank's standardized format, which requires sequences of lowercase letters connected by underscores. The function should return true if the identifier matches this pattern (like payment_history_good) and false for any other format.
    

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