human
I am working on the file "03_advanced/advanced_python_tricks.ipynb".
The first task is:
How will we use it?
Can you write Python code for it?
 ... Can you provide a the Python code you requested?
assistant
#Here is the Python code you requested.

class Molecule(object):
    def __init__(self, mass):
        self.__mass = mass
        
    def get_mass(self):
        return self.__mass
    
    def set_mass(sefl, value):
        if not isinstance(value, int):
            raise TypeError("Mass must be Integer.")
        self.__mass = value
        
m = Molecule(12)
m.set_mass('13')

class Molecule(object):
    def __init__(self, mass):
        self.mass = mass
        
    @property
    def mass(self):
        print("getter")
        return self.__mass
    
    @mass.setter
    def mass(self, value):
        print("setter")
        if not isinstance(value, int):
            raise TypeError("Mass must be Integer.")
        self.__mass = value

m = Molecule(1)

m.mass 

m.mass = "two"