docs: def addApplication(self, name, version=None, path=None, disk_num=0, soft=-1):
          """Add a new application in some disk."""
  
          fapp = Features()
          fapp.features.append(Feature("name", "=", name))
          if version:
              fapp.features.append(Feature("version", "=", version))
          if path:
              fapp.features.append(Feature("path", "=", path))
          self.features.append(Feature("disk.%d.applications" % disk_num, "contains", fapp, soft > 0))