how to check if a polynom is a square

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First of all, there is a function to check if a polynomial is a square

sage: x = polygen(GF(7))
sage: p = 2*x^2 + 6*x + 1
sage: p.is_square()
True

Then you need to learn about conditional statements in Python (if/elif/else): https://docs.python.org/3/tutorial/co...