code: def copy(self, src, dst, label=None):
      
      dst = self._normalize(dst)
      self._tag(dst, label)
      self._ensure_parent(dst)
      shutil.copy(src, os.path.join(self.chroot, dst))
docs: Copy file ``src`` to ``chroot/dst`` with optional label.
  
      May raise anything shutil.copy can raise, e.g.
        IOError(Errno 21 'EISDIR')
  
      May raise ChrootTaggingException if dst is already in a fileset
      but with a different label.