From the doc,
Modes ‘r+’, ‘w+’ and ‘a+’ open the file for updating (note that ‘w+’ truncates the file). Append ‘b’ to the mode to open the file in binary mode, on systems that differentiate between binary and text files; on systems that don’t have this distinction, adding the ‘b’ has no effect.
and here
w+ : Opens a file for both writing and reading. Overwrites the existing file if the file exists. If the file does not exist, creates a new file for reading and writing.
But, how to read a file open with w+?
