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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 visit_ImportFrom(self, node):
 """ Check validity of imported functions. Check: - no level specific value are provided. - a module is provided - module/submodule exists in MODULES - imported function exists in the given module/submodule """

        if node.level:
            raise PythranSyntaxError("Relative import not supported", node)
        if not node.module:
            raise PythranSyntaxError("import from without module", node)
        module = node.module
        current_module = MODULES
        # Check if module exists
        for path in module.split('.'):
            if path not in current_module:
                raise PythranSyntaxError(
                    "Module '{0}' unknown.".format(module),
                    node)
            else:
                current_module = current_module[path]

        # Check if imported functions exist
        for alias in node.names:
            if alias.name == '*':
                continue
            elif alias.name not in current_module:
                raise PythranSyntaxError(
                    "identifier '{0}' not found in module '{1}'".format(
                        alias.name,
                        module),
                    node)