Flatten nested Object

Objective: Write a function that takes a deeply nested object and returns a flat object with all keys flattened.

Instructions:

1. Create a function called flattenObject that accepts an object with nested objects at various levels.
2. The function should return a new object where all nested keys are flattened into a single-level object, with the keys representing the nested structure using dot notation (e.g., 'key1.key2': value).

Example:

flattenObject({
  a: 1,
  b: { 
    c: 2, 
    d: { 
      e: 3 
    }
  }
});
// Output: { 'a': 1, 'b.c': 2, 'b.d.e': 3 }

Requirements:

• The function must handle objects with multiple levels of nesting.
• The function should work recursively to flatten deeply nested objects.
• You cannot use any built-in flattening utilities.

Hints:

1. Use recursion to flatten nested objects.
2. Use dot notation to concatenate keys as you go deeper into nested objects.

Bonus:

1. Add a second argument to the function that limits how deep the object should be flattened.