PyFloat_FromDouble should take a float64

[zjb0807]

// PyObject* PyFloat_FromDouble(double v)
// Return value: New reference.
// Create a PyFloatObject object from v, or NULL on failure.
func PyFloat_FromDouble(v float32) *PyObject {
return togo(C.PyFloat_FromDouble(C.double(v)))
}

[zjb0807]

another problem, when i use PyFloat_AsDouble function:
err: cannot use python.PyFloat_AsDouble(rate) (type float64) as type float32 in assignment

[sbinet]

python.PyFloat_AsDouble now returns a float64.
either change the type of the value being assigned to (from float32 to float64) or convert what python.PyFloat_AsDouble returns to a float32.