# Create new structure class and define its element

Hello. I have a problem with the Element class of a new structure. In detail, I am defining a new subclass of Polynomial Ring via

```
class MyElement(sage.rings.polynomial.multi_polynomial_element.MPolynomial_polydict):
pass
class MyAlgebra(sage.structure.unique_representation.UniqueRepresentation, sage.rings.polynomial.multi_polynomial_ring.MPolynomialRing_polydict):
Element=MyElement
```

Now, I have:

```
sage: A=MyAlgebra(QQ,1,'x',order="lex")
sage: (x,)=A.gens()
sage: type(x)
<class 'sage.rings.polynomial.multi_polynomial_element.MPolynomial_polydict'>
```

While:

```
sage: a=MyElement(A,{(1,):1})
sage: type(a)
<class '__main__.MyElement'>
```

Why isn't the element x of type MyElement?