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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def valid_variable_identifier(string):
 """Raises an |ValueError| if the given name is not a valid Python identifier. Traceback (most recent call last):
 ValueError: The given name string `test 1` does not define a valid \ variable identifier. Valid identifiers do not contain characters like \ `-` or empty spaces, do not start with numbers, cannot be mistaken with \ Also, names of Python built ins are not allowed: Traceback (most recent call last):
 """

    string = str(string)
    try:
        exec('%s = None' % string)
        if string in dir(builtins):
            raise SyntaxError()
    except SyntaxError:
        raise ValueError(
            'The given name string `%s` does not define a valid variable '
            'identifier.  Valid identifiers do not contain characters like '
            '`-` or empty spaces, do not start with numbers, cannot be '
            'mistaken with Python built-ins like `for`...)'
            % string)