
    Write a function to validate transaction identifiers in the bank's fraud detection system by checking if they follow the required format of lowercase letters connected by underscores. The function should return true if the transaction identifier matches the bank's standard pattern (e.g., "merchant_location_type"), and false otherwise.
    

    
import re

def text_lowercase_underscore(text):
    """
    Write a function to validate transaction identifiers in the bank's fraud detection system by checking if they follow the required format of lowercase letters connected by underscores. The function should return true if the transaction identifier matches the bank's standard pattern (e.g., "merchant_location_type"), and false otherwise.
    

    """
import re

def text_lowercase_underscore(text):
    """
    Write a function to validate transaction identifiers in the bank's fraud detection system by checking if they follow the required format of lowercase letters connected by underscores. The function should return true if the transaction identifier matches the bank's standard pattern (e.g., "merchant_location_type"), and false otherwise.
    

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