Update README.md

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2-Working-With-Data/07-python/README.md

@@ -52,7 +52,7 @@ Pandas is centered around a few basic concepts.
 
 ### Series 
 
-**Series** is a sequence of values, similar to a list or numpy array. The main difference is that series also has and **index**, and when we operate on series (eg., add them), the index is taken into account. Index can be as simple as integer row number (it is the index used by default when creating a series from list or array), or it can have a complex structure, such as date interval.
+**Series** is a sequence of values, similar to a list or numpy array. The main difference is that series also has an **index**, and when we operate on series (eg., add them), the index is taken into account. Index can be as simple as integer row number (it is the index used by default when creating a series from list or array), or it can have a complex structure, such as date interval.
 
 > **Note**: There is some introductory Pandas code in the accompanying notebook [`notebook.ipynb`](notebook.ipynb). We only outline some the examples here, and you are definitely welcome to check out the full notebook.