docs: def _magic_signature_files(self, system_only=False, user_only=False):
          '''
          Find all user/system magic signature files.
  
          @system_only - If True, only the system magic file directory will be searched.
          @user_only   - If True, only the user magic file directory will be searched.
  
          Returns a list of user/system magic signature files.
          '''
          files = []
          user_binarch = self._user_path(self.BINWALK_MAGIC_DIR, self.BINARCH_MAGIC_FILE)
          system_binarch = self._system_path(self.BINWALK_MAGIC_DIR, self.BINARCH_MAGIC_FILE)
  
          def list_files(dir_path):
              # Ignore hidden dotfiles.
              return [os.path.join(dir_path, x) for x in os.listdir(dir_path) if not x.startswith('.')]
  
          if not system_only:
              user_dir = os.path.join(self.user_dir, self.BINWALK_USER_DIR, self.BINWALK_MAGIC_DIR)
              files += list_files(user_dir)
          if not user_only:
              system_dir = os.path.join(self.system_dir, self.BINWALK_MAGIC_DIR)
              files += list_files(system_dir)
  
          # Don't include binarch signatures in the default list of signature files.
          # It is specifically loaded when -A is specified on the command line.
          if user_binarch in files:
              files.remove(user_binarch)
          if system_binarch in files:
              files.remove(system_binarch)
  
          return files