I have in a directory `'C:/Users/lamda/Desktop/ML working/logs/a/'` multiple sub-directories and each sub-directory contains a bunch of files.my goal is to concatenate all these files in one file `'C:/Users/lamda/Desktop/ML working/logs/concatenate.log'`
I have wrote the following python code but it only succeeds in copying one file content in `'C:/Users/lamda/Desktop/ML working/logs/concatenate.log'`.I'm doubting that there a missing for loop but could not really figure out the issue.Please help me 

```
import glob
import os.path
directories = os.listdir('C:/Users/lamda/Desktop/ML working/logs/a')
for i in directories:
    files = os.listdir('C:/Users/lamda/Desktop/ML working/logs/a/' + i)
    print(files[1:])
    files2 = files[1:]
    for j in files2 :       
        fs = open('C:/Users/lamda/Desktop/ML working/logs/a/'+i+'/'+j,'r')
        fd = open('C:/Users/lamda/Desktop/ML working/logs/concatenate.log','w')
        #print(i)
        #print(j)
        for ligne in fs :
            fd.write(ligne)
fd.close()
fs.close()

```