    def visit_Call(self, node):
        """ A couple function calls are supported: bson's ObjectId() and
        datetime().
        """
        if isinstance(node.func, ast.Name):
            if node.func.id == 'ObjectId':
                try:
                    self.current_value = ObjectId(node.args[0].s)
                except:
                    pass
            elif node.func.id == 'datetime':
                values = []
                for arg in node.args:
                    values.append(arg.n)
                try:
                    self.current_value = datetime(*values)
                except:
                    pass
The software constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.