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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 merge_dicts(dicts, op=operator.add):
 """Merge a list of dictionaries. Args: dicts (list):
 a list of dictionary objects op (operator):
 an operator item used to merge the dictionaries. Defaults to :py:func:`operator.add`. Returns: dict: the merged dictionary """

    a = None
    for b in dicts:

        if a is None:
            a = b.copy()
        else:
            a = dict(a.items() + b.items() + [(k, op(a[k], b[k])) for k in set(b) & set(a)])
    return a