code: def add_symbols(namespace, registry):
      
      import unyt.unit_symbols as us
      from unyt.unit_object import Unit
  
      for name, unit in vars(us).items():
          if name.startswith("_"):
              continue
          namespace[name] = Unit(unit.expr, registry=registry)
      for name in [k for k in registry.keys() if k not in namespace]:
          namespace[name] = Unit(name, registry=registry)
docs: Adds the unit symbols from :mod:`unyt.unit_symbols` to a namespace
  
      Parameters
      ----------
  
      namespace : dict
         The dict to insert unit symbols into. The keys will be string
         unit names and values will be the corresponding unit objects.
      registry : :class:`unyt.unit_registry.UnitRegistry`
         The registry to create units from. Note that if you would like to
         use a custom unit system, ensure your registry was created using
         that unit system.
  
      Example
      -------
      >>> from unyt.unit_registry import UnitRegistry
      >>> class MyClass():
      ...     def __init__(self):
      ...         self.reg = UnitRegistry()
      ...         add_symbols(vars(self), self.reg)
      >>> foo = MyClass()
      >>> foo.kilometer
      km
      >>> foo.joule
      J