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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 validate_readable(option, value):
 """Validates that 'value' is file-like and readable. """

    if value is None:
        return value
    # First make sure its a string py3.3 open(True, 'r') succeeds
    # Used in ssl cert checking due to poor ssl module error reporting
    value = validate_string(option, value)
    open(value, 'r').close()
    return value