Entering shell mode, receiving 0x00 for any command that passes through python script

I am trying to extract the tag position through UART connected to the raspberry pi. When I enter the shell mode without using any script, the terminal won’t respond with “dwm>” to check if there is any data received while using a command such as led, lep etc. Tried using generic mode and tried to enter the shell mode using python script. Using DWM.readline enters into an infinite loop as it doesn’t get the newline character. So I tried using DWM.read function wherein it goes on reading single byte but I am receiving 0x00. Please find the attached image which clearly explains my scenario. Please do let me know if I am doing anything wrong because I am completely new to it and tried all my solutions which I thought might work (checked UART communication and debugging the code where might be the possibility of error could be)

Thanks and regards,