=======================================
From keyword can be a variable
=======================================
var a = Assert.Range(from, to);
---
(compilation_unit
(field_declaration
(variable_declaration
(implicit_type)
(variable_declarator
(identifier)
(equals_value_clause
(invocation_expression
(member_access_expression (identifier) (identifier))
(argument_list (argument (identifier)) (argument (identifier)))))))))