Validate give string is valid email address.

1. Define function 'validate_email' which will accept string as argument.
2. String should not be null.
3. Use regexp to validate email.
4. Use keyword pattern to define regex pattern.
5. Function should pass all test cases.

Instructions:

• Program should be written in file build.py

• Function name should be validate_email.

• Input

   Type:  String
   Value: [email protected]
  

• Expected Output

    Type:  Boolean
    Value: True