def find_ops(self, prefix=None, op_type=None, exactly_one=False):
        """
        Return list of ops with name matching `prefix` if specified, and
        op_type, if specified. At least one of {prefix, op_type} must be
        specified.

        If `exactly_one` == True, raise ValueError if we find <1 or >1 ops satisfying
        the criteria.

        prefix: str

        Return list[Operation]. Empty list if no op satisfies.
        """
        found_ops = []
        for f_name, f in self.functions.items():
            found_ops.extend(f.find_ops(prefix=prefix, op_type=op_type))
        if exactly_one and len(found_ops) != 1:
            msg = "Found matching ops not exactly one. Found ops: {}"
            raise ValueError(msg.format(found_ops))
        return found_ops

        Return list of ops with name matching `prefix` if specified, and
        op_type, if specified. At least one of {prefix, op_type} must be
        specified.

        If `exactly_one` == True, raise ValueError if we find <1 or >1 ops satisfying
        the criteria.

        prefix: str

        Return list[Operation]. Empty list if no op satisfies.
        
coremltools/converters/mil/mil/program.py