def decrypt_file(self, filename):
        '''
        Decrypt File
        Args:
            filename: Pass the filename to encrypt.
        Returns:
            No return.
        '''
        if not os.path.exists(filename):
            print "Invalid filename %s. Does not exist" % filename
            return

        if self.vault_password is None:
            print "ENV Variable PYANSI_VAULT_PASSWORD not set"
            return

        if not self.is_file_encrypted(filename):
            # No need to do anything.
            return

        cipher = 'AES256'
        vaulteditor = VaultEditor(cipher, self.vault_password, filename)
        vaulteditor.decrypt_file()