input: Write a python function to add a card and process payments using the CreditCardProcessor class.
  assert c = CreditCardProcessor(); c.add_card('1234', 'Alice'); c.process_payment('1234', 100); c.get_total_payments() == 100
  assert c = CreditCardProcessor(); c.add_card('5678', 'Bob'); c.process_payment('5678', 200); c.get_total_payments() == 200
  assert c = CreditCardProcessor(); c.add_card('9999', 'Charlie'); c.process_payment('9999', 300); c.get_total_payments() == 300
output: class CreditCardProcessor:
      def __init__(self):
          self.cards = {}
          self.total_payments = 0
  
      def add_card(self, card_number, card_holder):
          self.cards[card_number] = {'holder': card_holder, 'balance': 0}
  
      def process_payment(self, card_number, amount):
          if card_number in self.cards:
              self.cards[card_number]['balance'] += amount
              self.total_payments += amount
  
      def get_total_payments(self):
          return self.total_payments