human
Solve the following python programming problem given the following code:
def add_node(self, index) : 
    '
        Generate another node certificate.

        :rtype: CertAndKey
        :return: The newly created node certificate.
        ' 
    def run(* arguments) : 
        check_call (([b'flocker-ca'] + list (arguments)), cwd = self.directory.path) 
run (b'create-node-certificate') 
    tmp_crt = self.directory.globChildren (b'????????-????-*.crt') [0] 
    tmp_key = FilePath ((tmp_crt.path [: (- 3)] + b'key')) 
    crt = self.directory.child ((b'node-%d.crt' % (index,))) 
    key = self.directory.child ((b'node-%d.key' % (index,))) 
    tmp_crt.moveTo (crt) 
    tmp_key.moveTo (tmp_crt) 
    cert = CertAndKey (crt, key) 
    self.nodes.append (cert) 
    return cert 

    
    

    Fix the buggy line: tmp_key.moveTo (tmp_crt)
assistant
#Here is Python program to fix the buggy line: tmp_key.

tmp_key.moveTo (key)