code: def verify_certificate_chain(self, base=None, crt=None, csr=None, key=None):
          
          from burlap.common import get_verbose, print_fail, print_success
  
          r = self.local_renderer
  
          if base:
              crt = base + '.crt'
              csr = base + '.csr'
              key = base + '.key'
          else:
              assert crt and csr and key, 'If base not provided, crt and csr and key must be given.'
  
          assert os.path.isfile(crt)
          assert os.path.isfile(csr)
          assert os.path.isfile(key)
  
          csr_md5 = r.local('openssl req -noout -modulus -in %s | openssl md5' % csr, capture=True)
          key_md5 = r.local('openssl rsa -noout -modulus -in %s | openssl md5' % key, capture=True)
          crt_md5 = r.local('openssl x509 -noout -modulus -in %s | openssl md5' % crt, capture=True)
  
          match = crt_md5 == csr_md5 == key_md5
  
          if self.verbose or not match:
              print('crt:', crt_md5)
              print('csr:', csr_md5)
              print('key:', key_md5)
  
          if match:
              print_success('Files look good!')
          else:
              print_fail('Files no not match!')
              raise Exception('Files no not match!')
docs: Confirms the key, CSR, and certificate files all match.