code: def _name_available(self, obj, name, shaders):
          
          if name in self._global_ns:
              return False
          shaders = self.shaders if self._is_global(obj) else shaders
          for shader in shaders:
              if name in self._shader_ns[shader]:
                  return False
          return True
docs: Return True if *name* is available for *obj* in *shaders*.