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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 _build_field_choices(self, fields):
 """ Iterate over passed model fields tuple and update initial choices. """

        return tuple(sorted(
            [(fquery, capfirst(fname)) for fquery, fname in fields.items()],
            key=lambda f: f[1].lower())
        ) + self.FIELD_CHOICES