/in/foo.c:1:1: error: unknown type name 'def'
 def calculate_fee(amount):
 ^~~
/in/foo.c: In function 'calculate_fee':
/in/foo.c:1:26: error: expected declaration specifiers before ':' token
 def calculate_fee(amount):
                          ^
/in/foo.c:2:7: error: invalid preprocessing directive #�
     # 支付宝每月免费额度
       ^
/in/foo.c:4:7: error: invalid preprocessing directive #�
     # 手续费率
       ^
/in/foo.c:7:7: error: invalid preprocessing directive #�
     # 如果还款金额小于或等于免费额度，则手续费为0
       ^
/in/foo.c:11:11: error: invalid preprocessing directive #�
         # 超出部分计算手续费
           ^
/in/foo.c:17:3: error: invalid preprocessing directive #�
 # 示例：输入某月通过支付宝给信用卡还款的金额
   ^
/in/foo.c:20:3: error: invalid preprocessing directive #�
 # 计算手续费
   ^
/in/foo.c:23:3: error: invalid preprocessing directive #�
 # 输出结果
   ^
/in/foo.c:1:5: warning: type of 'amount' defaults to 'int' [-Wimplicit-int]
 def calculate_fee(amount):
     ^~~~~~~~~~~~~
/in/foo.c:24:1: warning: control reaches end of non-void function [-Wreturn-type]
 print(f"您需要支付的手续费为：{fee}元")
 ^~~~~