cs = open(r"session1.txt", "a+")
cs.write(i)
cs undefined, builtin open = <type 'file'>
IOError: [Errno 13] Permission denied: 'session1.txt'
args = (13, 'Permission denied')
errno = 13
filename = 'session1.txt'
strerror = 'Permission denied'
"
>>> help(open)
Help on class file in module __builtin__:
class file(object)
| file(name[, mode[, buffering]]) -> file object
|
| Open a file. The mode can be 'r', 'w' or 'a' for reading (default),
| writing or appending. The file will be created if it doesn't exist
| when opened for writing or appending; it will be truncated when
| opened for writing. Add a 'b' to the mode for binary files.
| Add a '+' to the mode to allow simultaneous reading and writing.
| If the buffering argument is given, 0 means unbuffered, 1 means line
| buffered, and larger numbers specify the buffer size.
| Add a 'U' to mode to open the file for input with universal newline
| support. Any line ending in the input file will be seen as a '\n'
| in Python. Also, a file so opened gains the attribute 'newlines';
| the value for this attribute is one of None (no newline read yet),
| '\r', '\n', '\r\n' or a tuple containing all the newline types seen.
|
| 'U' cannot be combined with 'w' or '+' mode.
|
| Note: open() is an alias for file()."
That last part is very pertainate to you situation.