Exploring and finding patterns/similarity in Data with Python

as I was learning Python,was working on one of the dataset like this:

**Col1**                                 **Col2**      **Col3**        
dog                                        Z             st02          
dog,cat                                    Z             st02          
dog,bat,cat                                Z             st02          
bat,cat,elephant                           Y             st02          
dog,bat,cat,elephant                       Y             st02          
tiger                                      Z             st01          
pigeon                                     Z             st01          
pigeon,parrot                              Z             st01          
dove,parrot                                Z             st01          
pigeon,parrot                              Z             st01          
pigeon,parrot,dove                         Z             st01          
lion,leopard,cheetah                       Z             st01          
tiger,lion,leopard,cheetah                 Z             st01          
dog,tiger,cheetah                          Y             st01          
dog,tiger,leopard,cheetah                  Y             st01          
eagle,jaguar,Kangaroo,zebra                Z             st02          
cheetah,eagle,jaguar,Kangaroo,zebra        Z             st02          

The expected output is:

**Col1**                                 **Col2**       **Col3**      
dog,bat,cat                                Z              st02          
dog,bat,cat,elephant                       Y              st02          
tiger,lion,leopard,cheetah                 Z              st01          
dog,tiger,leopard,cheetah                  Y              st01          
cheetah,eagle,jaguar,Kangaroo,zebra        Z              st02          
pigeon,parrot,dove                         Z              st01          

In order to extract the above rows as output, I tried tracing the patterns and using the below logic:

data = pd.read_excel("data.xlsx")
data['Col4'] = data['Col1'].str.count(',')
v1 = []
v2 = []
v1.append(0)
v2.append(0)
for i in range(0,data.shape[0]-1):
    x = data['Col_2'][i]
    y = data['Col_2'][i+1]
    t1 = data['Col_3'][i]
    t2 = data['Col_3'][i+1]
    g1 = (x == y) & (t1==t2)
    d1 = data['Col_1'][i]
    d2 = data['Col_1'][i+1]
    c1 = data['Col_4'][i]
    c2 = data['Col_4'][i+1]
    flag = 0
    if(all(x in d2 for x in d1)):
      flag = 1
    g2 = (flag == 1)&(c2>c1)
    v1.append(g1)
    v2.append(g2)
    data['new_cond1'] = v1   
    data['new_cond2'] = v2   
    data['Final_flag'] = (data['new_cond1']==True)&(data['new_cond2']==True) 
    data_output = data[data['Final_flag']==True]  

But I didn't end up getting the expected output, rather few additional rows are also present in output. Could someone please help me extracting the rows mentioned in expected output.

Thanks in advance!