code: async def root(self):
          
          if self.writing:
              await x.dump_uint(self.iobj, PortableStorageConsts.SIGNATUREA, 4)
              await x.dump_uint(self.iobj, PortableStorageConsts.SIGNATUREB, 4)
              await x.dump_uint(self.iobj, PortableStorageConsts.FORMAT_VER, 1)
  
          else:
              sig_a = await x.load_uint(self.iobj, 4)
              sig_b = await x.load_uint(self.iobj, 4)
              ver = await x.load_uint(self.iobj, 1)
  
              if sig_a != PortableStorageConsts.SIGNATUREA:
                  raise ValueError('Signature A error')
              if sig_b != PortableStorageConsts.SIGNATUREB:
                  raise ValueError('Signature A error')
              if ver != PortableStorageConsts.FORMAT_VER:
                  raise ValueError('Unsupported version')
docs: Root level init
          :return: