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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(self, schema):
 """ Merge the contents from the schema. Only objects not already contained in this schema's collections are merged. This is to provide for bidirectional import which produce cyclic includes. @returns: self @rtype: L{Schema} """

        for item in schema.attributes.items():
            if item[0] in self.attributes:
                continue
            self.all.append(item[1])
            self.attributes[item[0]] = item[1]
        for item in schema.elements.items():
            if item[0] in self.elements:
                continue
            self.all.append(item[1])
            self.elements[item[0]] = item[1]
        for item in schema.types.items():
            if item[0] in self.types:
                continue
            self.all.append(item[1])
            self.types[item[0]] = item[1]
        for item in schema.groups.items():
            if item[0] in self.groups:
                continue
            self.all.append(item[1])
            self.groups[item[0]] = item[1]
        for item in schema.agrps.items():
            if item[0] in self.agrps:
                continue
            self.all.append(item[1])
            self.agrps[item[0]] = item[1]
        schema.merged = True
        return self