code: def parse(self, data, extent):
          # type: (bytes, int) -> bool
          '''
          Do a parse of a Version Volume Descriptor.  This consists of seeing
          whether the data is either all zero or starts with 'MKI', and if so,
          setting the extent location of the Version Volume Descriptor properly.
  
          Parameters:
           data - The potential version data.
           extent - The location of the extent on the original ISO of this
                    Version Volume Descriptor.
          Returns:
           True if the data passed in is a Version Descriptor, False otherwise.
          '''
          if self._initialized:
              raise pycdlibexception.PyCdlibInternalError('This Version Volume Descriptor is already initialized')
  
          if data[:3] == b'MKI' or data == allzero:
              # OK, we have a version descriptor.
              self._data = data
              self.orig_extent_loc = extent
              self._initialized = True
              return True
  
          return Falsf parse(self, data, extent):
          # type: (bytes, int) -> bool
          '''
          Do a parse of a Version Volume Descriptor.  This consists of seeing
          whether the data is either all zero or starts with 'MKI', and if so,
          setting the extent location of the Version Volume Descriptor properly.
  
          Parameters:
           data - The potential version data.
           extent - The location of the extent on the original ISO of this
                    Version Volume Descriptor.
          Returns:
           True if the data passed in is a Version Descriptor, False otherwise.
          '''
          if self._initialized:
              raise pycdlibexception.PyCdlibInternalError('This Version Volume Descriptor is already initialized')
  
          if data[:3] == b'MKI' or data == allzero:
              # OK, we have a version descriptor.
              self._data = data
              self.orig_extent_loc = extent
              self._initialized = True
              return True
  
          return False
docs: Do a parse of a Version Volume Descriptor.  This consists of seeing
          whether the data is either all zero or starts with 'MKI', and if so,
          setting the extent location of the Version Volume Descriptor properly.
  
          Parameters:
           data - The potential version data.
           extent - The location of the extent on the original ISO of this
                    Version Volume Descriptor.
          Returns:
           True if the data passed in is a Version Descriptor, False otherwise.