code: def create_base_storage(self, logical_size, variant):
          
          if not isinstance(logical_size, baseinteger):
              raise TypeError("logical_size can only be an instance of type baseinteger")
          if not isinstance(variant, list):
              raise TypeError("variant can only be an instance of type list")
          for a in variant[:10]:
              if not isinstance(a, MediumVariant):
                  raise TypeError(
                          "array can only contain objects of type MediumVariant")
          progress = self._call("createBaseStorage",
                       in_p=[logical_size, variant])
          progress = IProgress(progress)
          return progress
docs: Starts creating a hard disk storage unit (fixed/dynamic, according
          to the variant flags) in the background. The previous storage unit
          created for this object, if any, must first be deleted using
          :py:func:`delete_storage` , otherwise the operation will fail.
          
          Before the operation starts, the medium is placed in
          :py:attr:`MediumState.creating`  state. If the create operation
          fails, the medium will be placed back in :py:attr:`MediumState.not_created` 
          state.
          
          After the returned progress object reports that the operation has
          successfully completed, the medium state will be set to :py:attr:`MediumState.created` , the medium will be remembered by this
          VirtualBox installation and may be attached to virtual machines.
  
          in logical_size of type int
              Maximum logical size of the medium in bytes.
  
          in variant of type :class:`MediumVariant`
              Exact image variant which should be created (as a combination of
              :py:class:`MediumVariant`  flags).
  
          return progress of type :class:`IProgress`
              Progress object to track the operation completion.
  
          raises :class:`VBoxErrorNotSupported`
              The variant of storage creation operation is not supported. See