human
remove non letters in string.
assistant
Here is a Python function to remove non letters from strings

import string

def remove_non_letters(s):
    """
    Remove non letters from a string.
    """
    return ''.join([c for c in s if c.isalpha()])

# Enter the string
s = "This is a string with non letters"

# Calling the function
print((remove_non_letters(s)))

#Example Output
# Thisisastringwithnonletters

#Remember to inspect code for bugs.