(self)
return self.args[-1].args
Returns the variables with which the function in the specified
        arbitrary expression is evaluated

        Examples
        ========

        >>> from sympy.physics.quantum.operator import DifferentialOperator
        >>> from sympy import Symbol, Function, Derivative
        >>> x = Symbol('x')
        >>> f = Function('f')
        >>> d = DifferentialOperator(1/x*Derivative(f(x), x), f(x))
        >>> d.variables
        (x,)
        >>> y = Symbol('y')
        >>> d = DifferentialOperator(Derivative(f(x, y), x) +
        ...                          Derivative(f(x, y), y), f(x, y))
        >>> d.variables
        (x, y)
Returns the variables with which the function in the specified
        arbitrary expression is evaluated
Returns the variables with which the function in the specified arbitrary expression is evaluated
def variables(self):
        """
        Returns the variables with which the function in the specified
        arbitrary expression is evaluated

        Examples
        ========

        >>> from sympy.physics.quantum.operator import DifferentialOperator
        >>> from sympy import Symbol, Function, Derivative
        >>> x = Symbol('x')
        >>> f = Function('f')
        >>> d = DifferentialOperator(1/x*Derivative(f(x), x), f(x))
        >>> d.variables
        (x,)
        >>> y = Symbol('y')
        >>> d = DifferentialOperator(Derivative(f(x, y), x) +
        ...                          Derivative(f(x, y), y), f(x, y))
        >>> d.variables
        (x, y)
        """

        return self.args[-1].args
def variables ( self ) : return self . args [ - 1 ] . args