public static String wildToSignature(WildcardType wt) {
		Type lower = wt.getLowerBounds().length == 0 ? null : wt.getLowerBounds()[0];
		Type upper = wt.getUpperBounds()[0];
		if (lower == null && upper == Object.class) {
			return "*";
		}
		if (lower == null) {
			return "+" + typeToSignature(upper);
		}
		if (upper == Object.class) {
			return "-" + typeToSignature(lower);
		}
		throw new UnsupportedOperationException();
	}
Get the signature of the given wildcard type

<ul>
<li>{@code sig(?) = *}</li>
<li>{@code sig(? super MyType) = -sig(MyType)}</li>
<li>{@code sig(? extends MyType) = +sig(MyType)}</li>
</ul>

@param wt the type
@return the signature
Ghidra/Framework/Emulation/src/main/java/ghidra/pcode/emu/jit/JitJvmTypeUtils.java