Explanation: Standard input, standard output and standard error. Standard input is the data that goes to the program. The standard input comes from a keyboard. Standard output is where we print our data with the print keyword. Unless redirected, it is the terminal console. The standard error is a stream where programs write their error messages. It is usually the text terminal.

Explanation: We have been working with simple textual data. What if we are working with objects rather than simple text? For such situations, we can use the pickle module. This module serializes Python objects. The Python objects are converted into byte streams and written to text files. This process is called pickling. The inverse operation, reading from a file and reconstructing objects is called deserializing or unpickling.

buffering: If the buffering value is set to 0, no buffering will take place. If the buffering value is 1, line buffering will be performed while accessing a file. If you specify the buffering value as an integer greater than 1, then buffering action will be performed with the indicated buffer size. If negative, the buffer size is the system default(default behavior).

Explanation: The method flush() flushes the internal buffer. Python automatically flushes the files when closing them. But you may want to flush the data before closing any file.