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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 validate( self, nanopub: Mapping[str, Any] ) -> Tuple[bool, List[Tuple[str, str]]]: """Validates using the nanopub schema Args: nanopub (Mapping[str, Any]):
 nanopub dict Returns: Tuple[bool, List[Tuple[str, str]]]: bool: Is valid? Yes = True, No = False List[Tuple[str, str]]: Validation issues, empty if valid, tuple is ('ERROR|WARNING', msg) e.g. [('WARNING', "Context ID not found")] """


        # Validate nanopub
        (is_valid, messages) = validate_to_schema(nanopub, self.nanopub_schema)
        if not is_valid:
            return messages

        # Extract BEL Version
        if nanopub["nanopub"]["type"]["name"].upper() == "BEL":
            bel_version = nanopub["nanopub"]["type"]["version"]
        else:
            is_valid = False
            return (
                is_valid,
                f"Not a BEL Nanopub according to nanopub.type.name: {nanopub['nanopub']['type']['name']}",
            )

        all_messages = []
        # Validate BEL Statements
        bel_obj = bel.lang.belobj.BEL(bel_version, self.endpoint)
        for edge in nanopub["nanopub"]["edges"]:
            bel_statement = f"{edge['subject']} {edge['relation']} {edge['object']}"
            parse_obj = bel_obj.parse(bel_statement)
            if not parse_obj.valid:
                all_messages.extend(
                    (
                        "ERROR",
                        f"BEL statement parse error {parse_obj.error}, {parse_obj.err_visual}",
                    )
                )

        # Validate nanopub.context
        for context in nanopub["nanopub"]["context"]:
            (is_valid, messages) = self.validate_context(context)
            all_messages.extend(messages)

        is_valid = True
        for _type, msg in all_messages:
            if _type == "ERROR":
                is_valid = False

        return (is_valid, all_messages)