class ConcException(Exception):  
    def __init__(self, message, eqn):  
        super().__init__(message)  
        self.eqn = eqn

class ThmFormatException(Exception):  
    def __init__(self, message, eqn):  
        super().__init__(message)  
        self.thm = eqn
        
class SimplifyException(Exception):  
    def __init__(self, message, eqn):  
        super().__init__(message)  
        self.thm = eqn