small typo: "varable" to "variable"
added "that" to "...definitions THAT can be used..."
small typo: "use" removed from "We can USE extract a part..."
Bad sentence corrected
"lists" replaced by "dictionaries", since this is what the text is reffering to
Fixed plural to singular
removed "the" from "of THE that particular class..."
small typo
small typo
typo
typos with "expection"
Merge pull request #6 from gfrubi/master

more small corrections to the text