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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 _iterate_fields_cond(self, pkt, val, use_val):
 """Internal function used by _find_fld_pkt & _find_fld_pkt_val"""

        # Iterate through the fields
        for fld, cond in self.flds:
            if isinstance(cond, tuple):
                if use_val:
                    if cond[1](pkt, val):
                        return fld
                    continue
                else:
                    cond = cond[0]
            if cond(pkt):
                return fld
        return self.dflt