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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 change_function_style(self, stripped_record, func_decl_style):
 """Converts a function definition syntax from the 'func_decl_style' to the one that has been set in self.apply_function_style and returns the string with the converted syntax."""

        if func_decl_style is None:
            return stripped_record
        if self.apply_function_style is None:
            # user does not want to enforce any specific function style
            return stripped_record
        regex = FUNCTION_STYLE_REGEX[func_decl_style]
        replacement = FUNCTION_STYLE_REPLACEMENT[self.apply_function_style]
        changed_record = re.sub(regex, replacement, stripped_record)
        return changed_record.strip()