code: def set_condition(self, conkey, val):
          
  
          if not any([conkey.startswith(c) for c in _COND_PREFIXES]):
              raise KeyError(conkey)
  
          if val in NONES:
              self.conditions[conkey] = None
          else:
              self.conditions[conkey] = str(val)
docs: Set condition conkey to value val. Convert val to str if not
          None.
  
          conkey: str
              A valid condition key.
  
          val: str, int, float, None
              Can always be None. Can be number or string depending on conkey.