def __init__ ( self, value, **metadata ):
        if type( value ) in MutableTypes:
            raise TraitError, \
                  "Cannot define a constant using a mutable list or dictionary"

        super( Constant, self ).__init__( value, **metadata )

#-------------------------------------------------------------------------------
#  'Delegate' trait:
#-------------------------------------------------------------------------------
Returns a constant, read-only trait whose value is *value*.
dataset/ETHPy150Open enthought/traits/traits/trait_types.py/Constant.__init__