Fix: Series' object is not callable

[Jack_Sparrow]

Hello there
this is my data set

Vote_count vote_average
2000 4,5
500 5
3500 4
3000 3,5
2700 4,5
1500 3,5

I want to count how many people (vote_count) gave which rating in one bar chart (x axis: rating_vote and y axis: vote_count)

this is my code

df_star_trek['vote_average']('vote_count').sum().plot(kind='bar');

I get this error message

TypeError                                 Traceback (most recent call last)
<ipython-input-102-d361146a8034> in <module>()
      1 #what is the vote avarage for Star Wars and Star Treck?
----> 2 df_star_trek['vote_average']('vote_count').sum().plot(kind='bar');

TypeError: 'Series' object is not callable

Why? How can I fix it?