def test_changing_expression():
"""Change expression and get value."""
formula = Formula("2*asin(x)", 16)
assert formula.get({"x": "1"}) == "3.1415926535897932384626433832795"
assert formula.expression == "2*asin(x)"
formula.set_expression("asin(x)")
assert formula.get({"x": "1"}) == "1.57079632679489661923132169163975"
formula.expression = "sin(x)"
assert formula.get({"x":
"1"}) == "0.8414709848078965066609974948209608755664"
