Bank Account Management

You are tasked with designing a class to manage banking operations. The class should include methods to perform two operations: "deposit" and "withdraw", with the amount. Ensure that the default balance of the account is 2500.
        
       Input:-deposit 1000
       Input Description: Input will have two different operations: "deposit" and "withdraw", followed by the amount. 
       Output: 3500.0
       Output Description: The output will be the current balance of the account, specified as a float. If an invalid operation is provided the program should display "invalid operation". If attempting to withdraw more amount than available, the program should display "insufficient fund". 
       Constraints: 
       Explanation: