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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 string(name, description, default=None):
 # type: (AName, ADescription, AStringDefault) -> AAnno """Add a string parameter to be passed when instantiating this YAML file"""

    args = common_args(name, default)
    return Anno(description, typ=str, **args)