Fix bug boltzman model agent giving money to itself (#28)

* fix bug where agent gives money to itself in the boltzmann model example
* [pre-commit.ci] auto fixes from pre-commit.com hooks

---------

Co-authored-by: Houssam Kherraz <[email protected]>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

Author: 3 people

boltzmann_wealth_model/model.py

@@ -62,7 +62,10 @@ def move(self):
 
     def give_money(self):
         cellmates = self.model.grid.get_cell_list_contents([self.pos])
-        if len(cellmates) > 1:
+        cellmates.pop(
+            cellmates.index(self)
+        )  # Ensure agent is not giving money to itself
+        if len(cellmates) > 0:
             other = self.random.choice(cellmates)
             other.wealth += 1
             self.wealth -= 1