新手求助：在使用json存储数据时出现以下报错

在编写用json存储数据的代码时出现以下报错，求大神解答~万分感谢~

代码如下：
import json

def enter_number():
filename=’favorite_number.json’
try:
with open(filename) as f_objt:
number=json.load(f_objt)
except FileNotFoundError:
number=input(“Enter your favorite number: “)
with open(filename, ‘w’) as f_objt:
json.dump(number, f_objt)
print(“Your favorite number %s has been remembered.”%(number))
else:
print(“I know your favorite number is %s!”%(number))

enter_number()

报错如下：
Traceback (most recent call last):
File “C:\Users\mame006\Udacity\favorite_number.py”, line 16, in
enter_number()
File “C:\Users\mame006\Udacity\favorite_number.py”, line 7, in enter_number
number=json.load(f_objt)
File “C:\Users\mame006\python\lib\json__init__.py”, line 299, in load
parse_constant=parse_constant, object_pairs_hook=object_pairs_hook, **kw)
File “C:\Users\mame006\python\lib\json__init__.py”, line 354, in loads
return _default_decoder.decode(s)
File “C:\Users\mame006\python\lib\json\decoder.py”, line 339, in decode
obj, end = self.raw_decode(s, idx=_w(s, 0).end())
File “C:\Users\mame006\python\lib\json\decoder.py”, line 357, in raw_decode
raise JSONDecodeError(“Expecting value”, s, err.value) from None
json.decoder.JSONDecodeError: Expecting value: line 1 column 1 (char 0)