The trickiest part may be getting your boundaries into a python list. If the data are in excel you will probably need to structure them in a table format so ArcGIS can read them that way,
FLD1 FLD2
poly1 1
x y
x y
x y
x y
poly2 2
x y
...
These would come in as two string fields, which you would then need run a SearchCursor loop over to construct Python data in a list like this:
["poly1", 1, [[x,y], [x,y], [x,y], [x,y]]]
["poly2", 2, [[x,y], .... ]]
Then, if there aren't holes involved, writing polygon geometry is pretty straight forward if you follow the steps:
- construct an array of points
- create a polygon geometry
- write to a shape field inside an update cursor
I believe the examples in the help are useful but way too sparse. Here's a script I posted to GeoNet that worked for me:
There are also many other examples on GeoNet and elsewhere to consult:
arcpy - Python script that creates polygon feature class with given coordinates (nice simple example)
Bug?: Creating polygons with holes using Arcpy
Examples of Geometry object - polygon and intersect