code: def add_variable(self, name, fetch_as=None):
          
          if fetch_as:
              self.variables.append(LogVariable(name, fetch_as))
          else:
              # We cannot determine the default type until we have connected. So
              # save the name and we will add these once we are connected.
              self.default_fetch_as.append(name)
docs: Add a new variable to the configuration.
  
          name - Complete name of the variable in the form group.name
          fetch_as - String representation of the type the variable should be
                     fetched as (i.e uint8_t, float, FP16, etc)
  
          If no fetch_as type is supplied, then the stored as type will be used
          (i.e the type of the fetched variable is the same as it's stored in the
          Crazyflie).