Check if property exists in object

// Write a function that takes an object (a) and a string (b) as argument
// Return true if a has a property with key b
// Return false otherwise
function
myFunction
(
a, b
)
{

return
}
Test Cases:
myFunction({a:1,b:2,c:3},'b')
Expected
true
myFunction({x:'a',y:'b',z:'c'},'a')
Expected
false
myFunction({x:'a',y:'b',z:'c'},'z')
Expected
true