def bind_variable(self, variable_name, variable_value):
str_name = str(variable_name)<EOL>prev = self.variables.get(str_name)<EOL>if prev != variable_value:<EOL><INDENT>self.variables[str(variable_name)] = variable_value<EOL>self.mod_count = self.mod_count + <NUM_LIT:1><EOL><DEDENT>
Bind a named variable to a value within the context
            This allows for passing in variables in testing