I need to build a script to interact with output from app commands. I used pexpect as in the code below.

import pexpect
import re
import sys

def script():
        p = pexpect.spawn(command, encoding='utf8')
        p.logfile = sys.stdout

        p.expect('Enter org code:')
        p.sendline('0123r')
        p.expect('The cost to maintain is $(d.d*)')

        price = p.match.groups()
        num = float(price[0])
        if num > 100:
           print("nnPrice is too high: ", price[0])
           p.sendline('nr')
        else:
           print("nPrice is good: ", price[0])
           p.expect('Do you want to continue? [y/n] (n):')
           p.sendline('yr')
           p.expect('Review:')
           p.interact()
           p.expect('Done')
           p.sendline('nnSucceeded')

The first expect p.expect('Enter org code:') worked well. However, I always faces issue with the second expect p.expect('The cost to maintain is $(d.d*)')

│ /root/scripts/r.py:18 in script                                                                  
│                                                                                                 
│   15 │   │   except:                                                                             
│   16 │   │   │   print("Exception was thrown")                                                   
│   17 │   │   │   print(str(p))                                                                   
│ ❱ 18 │   │   price = p.match.groups()                                                            
│   19 │   │   print(price)                                                                        
│   20 │   │   num = float(price[0])                                                               
│   21 │   │   if num > 100: 
AttributeError: 'NoneType' object has no attribute 'groups'

It seems that p.match.groups() was empty because the expect couldn’t match anything.

If I run p.expect('The cost to maintain is $(d.d*)') with output from echo (same text as output from application command), everything worked fine.
I suspect that spawn only send the first line output in uft8.
After p.sendline('0123r'), the output became bytes array again.

Any idea to overcome this? Is there any other way to work with output command?