code: def _apply_replacement(error, found_file, file_lines):
      
      fixed_lines = file_lines
      fixed_lines[error[1].line - 1] = error[1].replacement
      concatenated_fixed_lines = "".join(fixed_lines)
  
      # Only fix one error at a time
      found_file.seek(0)
      found_file.write(concatenated_fixed_lines)
      found_file.truncate()
docs: Apply a single replacement.