Hi,

What are the SymPy.jl analogues for `as_dict`

and `gens`

? See below for a minimal piece of code I would like to translate from SymPy to SymPy.jl. This is part of a larger project I am translating from Python to Julia which involves sum of squares of polynomials. Thanks in advance for any help!

```
from sympy import poly
poly = poly('5*y**7 + 3*x**2 + 2*x*y**2 + 1')
print(poly.as_dict()) # {(0, 0): 1, (0, 7): 5, (1, 2): 2, (2, 0): 3}
print(poly.gens) # (x, y)
```