code: def extent_size(self, units="MiB"):
          
          self.open()
          size = lvm_vg_get_extent_size(self.handle)
          self.close()
          return size_convert(size, units)
docs: Returns the volume group extent size in the given units. Default units are  MiB.
  
          *Args:*
  
          *       units (str):    Unit label ('MiB', 'GiB', etc...). Default is MiB.