[USER (data scientist)]: Lastly, I want to perform some statistical tests to see if there's a significant difference in win/loss ratios across surface types for each ranking group. Please conduct ANOVA tests to compare win/loss ratios across different surface types for each ranking group in the ATP tennis dataset.
My template of code snippet is:

---BEGIN CODE TEMPLATE---

import pandas as pd
import numpy as np
from scipy import stats 
import pickle

atp_tennis = pd.read_csv('atp_tennis.csv')

# YOUR SOLUTION BEGIN:
<code1>
[COMPLETE YOUR CODE] 
</code1>
# YOUR SOLUTION END

print(anova_results)

# save data
pickle.dump(anova_results,open("./pred_result/anova_results.pkl","wb"))

---END CODE TEMPLATE---

[YOU (AI assistant)]: We can perform an ANOVA test for each ranking group to test for significant differences. Let's run the test and print the p-values to check for significant differences in win/loss ratios across surface types. Here's the code for that: 
'''
import pandas as pd
import numpy as np
from scipy import stats 
import pickle

atp_tennis = pd.read_csv('atp_tennis.csv')

# YOUR SOLUTION BEGIN:
