chore: add helper methods

crates/els/semantic.rs

@@ -187,7 +187,7 @@ impl ASTSemanticState {
         if let Some(t_spec) = def.sig.t_spec() {
             tokens.extend(self.gen_from_typespec(t_spec.clone()));
         }*/
-        let params = def.sig.params();
+        let params = def.sig.into_params();
         tokens.extend(self.gen_from_block(params, def.body.block));
         tokens
     }

crates/erg_compiler/context/inquire.rs

@@ -2134,6 +2134,7 @@ impl Context {
         let there_var = var_args.is_some() || kw_var_args.is_some();
         if (params_len < pos_args.len()
             || params_len < pos_args.len() + kw_args.len()
+            // if there are extra *args or **kwargs
             || (params_len == pos_args.len() + kw_args.len() && there_var))
             && subr.is_no_var()
         {

crates/erg_parser/ast.rs

@@ -6246,13 +6246,20 @@ impl Signature {
         }
     }
 
-    pub fn params(self) -> Option<Params> {
+    pub fn into_params(self) -> Option<Params> {
         match self {
             Self::Var(_) => None,
             Self::Subr(subr) => Some(subr.params),
         }
     }
 
+    pub fn params(&self) -> Option<&Params> {
+        match self {
+            Self::Var(_) => None,
+            Self::Subr(subr) => Some(&subr.params),
+        }
+    }
+
     pub fn decorators(&self) -> Option<&HashSet<Decorator>> {
         match self {
             Self::Var(_) => None,
@@ -6954,6 +6961,25 @@ impl Expr {
         ))
     }
 
+    pub fn method_call(self, ident: Identifier, args: Args) -> Call {
+        Call::new(self, Some(ident), args)
+    }
+
+    pub fn method_call_expr(self, ident: Identifier, args: Args) -> Self {
+        Self::Call(self.method_call(ident, args))
+    }
+
+    pub fn method_call1(self, ident: Identifier, expr: Expr) -> Self {
+        self.method_call_expr(ident, Args::pos_only(vec![PosArg::new(expr)], None))
+    }
+
+    pub fn method_call2(self, ident: Identifier, expr1: Expr, expr2: Expr) -> Self {
+        self.method_call_expr(
+            ident,
+            Args::pos_only(vec![PosArg::new(expr1), PosArg::new(expr2)], None),
+        )
+    }
+
     pub fn type_asc(self, t_spec: TypeSpecWithOp) -> TypeAscription {
         TypeAscription::new(self, t_spec)
     }