code: def pay_cost(self, source, amount: int) -> int:
  		
  		if self.spells_cost_health and source.type == CardType.SPELL:
  			self.log("%s spells cost %i health", self, amount)
  			self.game.queue_actions(self, [Hit(self.hero, amount)])
  			return amount
  		if self.temp_mana:
  			# Coin, Innervate etc
  			used_temp = min(self.temp_mana, amount)
  			amount -= used_temp
  			self.temp_mana -= used_temp
  		self.log("%s pays %i mana", self, amount)
  		self.used_mana += amount
  		return amount
docs: Make player pay \a amount mana.
  		Returns how much mana is spent, after temporary mana adjustments.