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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 compute_report(self, texts, context_size=10):
 """Compute statistics of invalid characters on given texts. Parameters texts: list of str The texts to search for invalid characters. context_size: int How many characters to return as the context. Returns ------- dict of (char -> list of tuple (index, context)) Returns a dictionary, where keys are invalid characters. Values are lists containign tuples with character indices and context strings. """

        result = defaultdict(list)
        for text in texts:
            for char, examples in self.find_invalid_chars(text, context_size).items():
                result[char].extend(examples)
        return result