<human>:  valiate filename check user input reg ex.
<bot>: Here is a Python program to validate filenames and check user input

import os

def valid_filename(filename):
  """Validate a filename.

  Args:
    filename (str): The filename to validate.

  Returns:
    bool: True if the filename is valid, False otherwise.
  """
  if not isinstance(filename, str):
    return False
  if not filename:
    return False
  if not os.path.isfile(filename):
    return False
  return True

# Enter the filename
filename = "/home/rosey/Desktop/test.txt"

# Calling the function
print((valid_filename(filename)))

#Example Output
# False

#Remember to inspect code for bugs.