code: def fmt(self, fills):
          
          f = "%(identifier)s%(ws)s{%(nl)s%(proplist)s}%(eb)s"
          out = []
          name = self.name.fmt(fills)
          if self.parsed and any(
                  p for p in self.parsed
                  if str(type(p)) != "<class 'lesscpy.plib.variable.Variable'>"):
              fills.update({
                  'identifier':
                  name,
                  'proplist':
                  ''.join([p.fmt(fills) for p in self.parsed if p]),
              })
              out.append(f % fills)
          if hasattr(self, 'inner'):
              if self.name.subparse and len(self.inner) > 0:  # @media
                  inner = ''.join([p.fmt(fills) for p in self.inner])
                  inner = inner.replace(fills['nl'],
                                        fills['nl'] + fills['tab']).rstrip(
                                            fills['tab'])
                  if not fills['nl']:
                      inner = inner.strip()
                  fills.update({
                      'identifier': name,
                      'proplist': fills['tab'] + inner
                  })
                  out.append(f % fills)
              else:
                  out.append(''.join([p.fmt(fills) for p in self.inner]))
          return ''.join(out)
docs: Format block (CSS)
          args:
              fills (dict): Fill elements
          returns:
              str (CSS)