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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 header_param(name, required=False, param_type="string"):
 """ Build a header parameter definition. """

    return swagger.HeaderParameterSubSchema(**{
        "name": name,
        "in": "header",
        "required": required,
        "type": param_type,
    })