Write a function to merge two dictionaries.
def merge_dict(d1,d2):
 d = d1.copy()
 d.update(d2)
 return d
<s>[INST]<<SYS>>Given a task and its code, generate test cases for the code.<</SYS>>Write a function to merge two dictionaries.
def merge_dict(d1,d2):
 d = d1.copy()
 d.update(d2)
 return d[/INST]assert merge_dict({'a': 100, 'b': 200},{'x': 300, 'y': 200})=={'x': 300, 'y': 200, 'a': 100, 'b': 200}
assert merge_dict({'a':900,'b':900,'d':900},{'a':900,'b':900,'d':900})=={'a':900,'b':900,'d':900,'a':900,'b':900,'d':900}
assert merge_dict({'a':10,'b':20},{'x':30,'y':40})=={'x':30,'y':40,'a':10,'b':20}</s>