Bar Chart in Python Jupyter Lab Not Plotting Instead Throwing Errors

Question

So, I am working on a data analytic project and I want to create a bar graph so on the dataset I have already used the groupby function to group the Month column in other to find the highest sales in a particular month using the following function -

all_monthly_sales['Sales']=all_monthly_sales['Quantity Ordered']*all_monthly_sales['Price Each']
all_monthly_sales.head()

giving the following result as attached.

Then I created a BAR chart using the following function -

months = range (1,13)

plt.bar(months, results['Sales'])
plt.xticks(Month)
plt.ylabel('Sales in USD')
plt.xlabel('Month')
plt.show()

And I got an error as -

``---------------------------------------------------------------------------
KeyError                                  Traceback (most recent call last)
~\anaconda3\lib\site-packages\pandas\core\indexes\base.py in get_loc(self, key, method, tolerance)
   3628             try:
-> 3629                 return self._engine.get_loc(casted_key)
   3630             except KeyError as err:

~\anaconda3\lib\site-packages\pandas\_libs\index.pyx in pandas._libs.index.IndexEngine.get_loc()

~\anaconda3\lib\site-packages\pandas\_libs\index.pyx in pandas._libs.index.IndexEngine.get_loc()

pandas\_libs\hashtable_class_helper.pxi in pandas._libs.hashtable.PyObjectHashTable.get_item()

pandas\_libs\hashtable_class_helper.pxi in pandas._libs.hashtable.PyObjectHashTable.get_item()

KeyError: 'Sales'

The above exception was the direct cause of the following exception:

KeyError                                  Traceback (most recent call last)
~\AppData\Local\Temp\ipykernel_1984\3325122330.py in <module>
      1 months = range (1,13)
      2 
----> 3 plt.bar(months, results['Sales'])
      4 plt.xticks(Month)
      5 plt.ylabel('Sales in USD')

~\anaconda3\lib\site-packages\pandas\core\frame.py in __getitem__(self, key)
   3503             if self.columns.nlevels > 1:
   3504                 return self._getitem_multilevel(key)
-> 3505             indexer = self.columns.get_loc(key)
   3506             if is_integer(indexer):
   3507                 indexer = [indexer]

~\anaconda3\lib\site-packages\pandas\core\indexes\base.py in get_loc(self, key, method, tolerance)
   3629                 return self._engine.get_loc(casted_key)
   3630             except KeyError as err:
-> 3631                 raise KeyError(key) from err
   3632             except TypeError:
   3633                 # If we have a listlike key, _check_indexing_error will raise

KeyError: 'Sales'

Tried plotting a graph but I was getting an error any help will be appreciated.