如何避免在使用字典理解时出现缺少键的错误

my_dict = {'key1': 'value1', 'key2': 'value2'}
value = my_dict.get('key3', 'default_value')

my_dict = {'key1': 'value1', 'key2': 'value2'}
if 'key3' in my_dict:
    value = my_dict['key3']
else:
    value = 'default_value'

my_dict = {'key1': 'value1', 'key2': 'value2'}
try:
    value = my_dict['key3']
except KeyError:
    value = 'default_value'