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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 format_field(self, value, format_spec):
 """When field missing, return original spec."""

        if isinstance(value, MissingField):
            if format_spec is not None:
                value.format_spec = format_spec
            return str(value)

        return super(FormatterWrapper, self).format_field(value, format_spec)