Merge pull request #362 from ecmendenhall/python-lesson-2-typo-fix

Python: tiny typo fix

Author: matyikriszta

python/lesson2/tutorial.md

@@ -80,7 +80,7 @@ multiple *types* of objects that you work with in Python, and they don't all
 act the same way.  The three types you've learnt so far are *integers* (`int`),
 *floats* (`float`), and *strings* (`str`). Integers are whole numbers, floats 
 are numbers with a decimal point, and strings are any number of characters 
-surrounded be either "" or ''. This is important to know because every Python 
+surrounded by either "" or ''. This is important to know because every Python 
 programmer has tried to do this at least once in their career:
 
     "7" + 8