I want to merge two dictionaries into a new dictionary.
```
x = {'a': 1, 'b': 2}
y = {'b': 3, 'c': 4}
z = merge(x, y)

&gt;&gt;&gt; z
{'a': 1, 'b': 3, 'c': 4}
```
Here's how you can merge two dictionaries in Python:
```python
z = {**x, **y}
```
Or you can use the `dict.update()` method:
```python
z = x.copy()
z.update(y)
```
Both methods will create a new dictionary `z` with the combined keys and values from `x` and `y`.
The `merge` function should take care of merging the values when the keys are the same, but should not overwrite keys that are unique to either `x` or `y`.

To accomplish this, we'll use the `|` operator, which performs a dictionary merge. This operator was introduced in Python 3.5. If you're using an older version of Python, you'll need to use a custom merge function.

Here's how