📝 **Question:** Build a \`length(x)\` using \`@singledispatch\` that returns:\n- for str: \`len(x) * 2\`\n- default (any other type): \`-1\`\nPrint \`length("hi")\` and \`length(42)\`.\nExpected:\n4\n-1 📋 Pick the right answer. 💡 **Hint:** Re-read the theory above if unsure.