#NEWLINE# @ property #NEWLINE# def free_symbols( self ) : #NEWLINE# #INDENT# '\n        This method returns the symbols in the object, excluding those\n        that take on a specific value (i.e. the dummy symbols).\n\n        Examples\n        ========\n\n        >>> from sympy import SeqFormula\n        >>> from sympy.abc import n, m\n        >>> SeqFormula(m*n**2, (n, 0, 5)).free_symbols\n        set([m])\n        ' #NEWLINE# return set ( ( j for i in self . args for j in i . free_symbols . difference ( j . variables ) ) )