How to read Python Documentation -

i'm trying understand how should read python documentation, example given:
string.lstrip(s[, chars])
how should read that? know brackets means optional, 's', mean? there page explains how documentation written?

it's not explictly defined in documentation, in

string.lstrip(s[, chars]) 

string python module, not string (e.g. can't "abc").

the parameter s string (e.g. can "abc") want strip. it's mandatory, not optional.

the bracket-enclosed parameter optional, string , characters stripped string.

some examples of how call function are:

import string  print string.lstrip("abc", "a") # "bc" print string.lstrip(" abc") # "abc" 

note: don't confuse "abc".lstrip(). different functions identical results. also, read @user2357112's comment.

edit: on ide i've tested , shows s on docs (pressing f2):

def lstrip found at: string  def lstrip(s, chars=none):     """lstrip(s [,chars]) -> string      return copy of string s leading whitespace removed.     if chars given , not none, remove characters in chars instead.      """     return s.lstrip(chars)  # strip trailing tabs , spaces