code: def get_command(self, mode, txt=''):
          
          if mode == 'COMMAND':
              self.prompt = '> '
          elif mode == 'ADD':
              self.prompt = 'ADD > '
          elif mode == 'QUERY':
              self.prompt = '?? > '
          if txt == '':
              txt = input(self.prompt)
          return txt
docs: Takes a raw user input, initially from command line
          Later: 
              - check user credentials
              - rate bias
              - check for malicious commands