renumbering section usin secnum

to follow the numbering of python-course project

source/Collection_Data_Types.rst

+.. sectnum::
+   :start: 5
+   
 .. _Collection_Data_types:
 
 *********************

source/Control_Flow_Statements.rst

+.. sectnum::
+   :start: 7
+
 .. _Control_Flow_Statements:
 
 

source/Data_Types.rst

+.. sectnum::
+   :start: 4
+   
 .. _Data_Types:
 
 **********

source/Dive_into_Functions.rst

+.. sectnum::
+   :start: 8
+
 .. _Dive_into_Functions:
 
 *******************

source/Input_Output.rst

+.. sectnum::
+   :start: 10
+
 .. _Input_Output:
 
 ****************

source/Modules_and_Packages.rst

+.. sectnum::
+   :start: 9
+
 .. _Modules_and_Packages:
 
 ********************

source/index.rst

@@ -10,13 +10,9 @@ Contents:
 
 .. toctree::
    :maxdepth: 2
-   :numbered:
    
-   Introduction
-   Variables
    Data_Types
    Collection_Data_Types
-   Logical_Operations
    Control_Flow_Statements
    Dive_into_Functions
    Modules_and_Packages