ANOVA: DataFrame ha no Attribute alpha

[Tese]

I'm a beginner in Python, but familiar with statistics. I'm trying to conduct Two Way ANOVA analysis in the use of Python examples from blogs. Specifically, I want to test two detergent brands, called Top and Alpha, in the use of cold and hot water. In the end, I can determine water temperature has in an effect on the effectiveness of detergents.
But, unfortunately, I faced with errors in the beginning on in interaction plot construction and on the degree of freedom calculation as indicated below. I have enclosed below details, hypothetical data, codes, and errors. Please help me!

import pandas as pd
from statsmodels.formula.api import ols
from statsmodels.stats.anova import anova_lm
from statsmodels.graphics.factorplots import interaction_plot
import matplotlib.pyplot as plt
from scipy import stats

data = pd.read_csv('C:\\Users\\Tesema\\Desktop\\PYTHON\\PYTHON3\\Deterent2.csv')
print(data)

Output:
   "Detergent_Brands"; "Cold";  "Hot"
0              "top";      4;     10
1            "alpha";      5;     10
2              "top";      6;     12
3            "alpha";      5;     13
4              "top";      6;     11
5            "alpha";      5;     10
6              "top";      4;     12
7            "alpha";      6;     11
8              "top";      4;     12
9            "alpha";      5;     10
10             "top";      6;     11
11           "alpha";      5;     12
12             "top";      6;     10
13           "alpha";      5;     10

N = len(data.len)

df_a = len(data.top.unique()) - 1

df_b = len(data.alpha.unique()) - 1

df_axb = df_a*df_b 

df_w = N - (len(data.top.unique())*len(data.alpha.unique()))

Error:
---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
<ipython-input-7-b9e8e4474b44> in <module>
----> 1 N = len(data.len)
      2 df_a = len(data.top.unique()) - 1
      3 df_b = len(data.alpha.unique()) - 1
      4 df_axb = df_a*df_b
      5 df_w = N - (len(data.top.unique())*len(data.alpha.unique()))

~\Anaconda3\lib\site-packages\pandas\core\generic.py in __getattr__(self, name)
   5065             if self._info_axis._can_hold_identifiers_and_holds_name(name):
   5066                 return self[name]
-> 5067             return object.__getattribute__(self, name)
   5068 
   5069     def __setattr__(self, name, value):

AttributeError: 'DataFrame' object has no attribute 'len'

fig = interaction_plot(data.alpha, data.top, data.len,

             colors=['red','blue'], markers=['D','^'], ms=11)

Error:
---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
<ipython-input-9-6c5947e09274> in <module>
----> 1 fig = interaction_plot(data.alpha, data.top, data.len,
      2              colors=['red','blue'], markers=['D','^'], ms=11)

~\Anaconda3\lib\site-packages\pandas\core\generic.py in __getattr__(self, name)
   5065             if self._info_axis._can_hold_identifiers_and_holds_name(name):
   5066                 return self[name]
-> 5067             return object.__getattribute__(self, name)
   5068 
   5069     def __setattr__(self, name, value):

AttributeError: 'DataFrame' object has no attribute 'alpha'