<human>:  how to add something to a text file in.
<bot>: Here is a Python function to add something to a text file

import os

def add_to_file(file_name, text):
  """
  Add text to a file.
  """
  with open(file_name, 'a') as f:
    f.write(text)

# Enter the file name
file_name = 'test.txt'

# Enter the text to be added
text = 'This is a test'

# Calling the function
print((add_to_file(file_name, text)))

#Example Output
# None

#Remember to inspect code for bugs.