Human: Python program to normalize text string. Assistant: 
Here is a Python program to normalize text strings

import re

def normalize_text(text):
    """Normalize text string"""
    return re.sub(r'([^a-zA-Z0-9 ])', lambda m: (m.group(1).lower()), text)

# Enter the string
string = "carnation"

# Calling the function
print((normalize_text(string)))

#Example Output
# carnation

#Remember to inspect code for bugs.