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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 set_field_at(self, index, *, name, value, inline=True):
 """Modifies a field to the embed object. The index must point to a valid pre-existing field. This function returns the class instance to allow for fluent-style chaining. Parameters index: :class:`int` The index of the field to modify. name: :class:`str` The name of the field. value: :class:`str` The value of the field. inline: :class:`bool` Whether the field should be displayed inline. Raises ------- IndexError An invalid index was provided. """


        try:
            field = self._fields[index]
        except (TypeError, IndexError, AttributeError):
            raise IndexError('field index out of range')

        field['name'] = str(name)
        field['value'] = str(value)
        field['inline'] = inline
        return self