diff --git a/python/python-ast/src/com/jetbrains/python/ast/PyAstNamedParameter.java b/python/python-ast/src/com/jetbrains/python/ast/PyAstNamedParameter.java
index 25ed95f725fe..5f30e25a7938 100644
--- a/python/python-ast/src/com/jetbrains/python/ast/PyAstNamedParameter.java
+++ b/python/python-ast/src/com/jetbrains/python/ast/PyAstNamedParameter.java
@@ -17,9 +17,7 @@ package com.jetbrains.python.ast;
 
 import com.intellij.lang.ASTNode;
 import com.intellij.psi.*;
-import com.intellij.psi.stubs.IStubElementType;
-import com.intellij.psi.stubs.StubElement;
-import com.jetbrains.python.PyElementTypes;
+import com.intellij.util.ObjectUtils;
 import com.jetbrains.python.PyTokenTypes;
 import com.jetbrains.python.PythonDialectsTokenSetProvider;
 import com.jetbrains.python.ast.impl.ParamHelperCore;
@@ -94,7 +92,17 @@ public interface PyAstNamedParameter extends PyAstParameter, PsiNamedElement, Ps
    * Includes asterisks for *param and **param, and name.
    */
   @NotNull
-  String getRepr(boolean includeDefaultValue);
+  default String getRepr(boolean includeDefaultValue) {
+    final StringBuilder sb = new StringBuilder();
+
+    sb.append(ParamHelperCore.getNameInSignature(this));
+
+    if (includeDefaultValue) {
+      sb.append(ObjectUtils.notNull(ParamHelperCore.getDefaultValuePartInSignature(getDefaultValueText(), false), ""));
+    }
+
+    return sb.toString();
+  }
 
   @Override
   @NotNull
diff --git a/python/python-ast/src/com/jetbrains/python/ast/impl/ParamHelperCore.java b/python/python-ast/src/com/jetbrains/python/ast/impl/ParamHelperCore.java
index 8440740928db..0bcf6adf8224 100644
--- a/python/python-ast/src/com/jetbrains/python/ast/impl/ParamHelperCore.java
+++ b/python/python-ast/src/com/jetbrains/python/ast/impl/ParamHelperCore.java
@@ -1,10 +1,14 @@
 package com.jetbrains.python.ast.impl;
 
 import com.intellij.openapi.util.Pair;
+import com.intellij.openapi.util.text.StringUtil;
 import com.jetbrains.python.ast.PyAstExpression;
+import com.jetbrains.python.ast.PyAstNamedParameter;
 import com.jetbrains.python.ast.PyAstStringLiteralExpression;
 import com.jetbrains.python.psi.PyStringLiteralCoreUtil;
 import org.jetbrains.annotations.ApiStatus;
+import org.jetbrains.annotations.Contract;
+import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
 @ApiStatus.Experimental
@@ -12,6 +16,49 @@ public final class ParamHelperCore {
   private ParamHelperCore() {
   }
 
+  @NotNull
+  public static String getNameInSignature(@NotNull PyAstNamedParameter parameter) {
+    final StringBuilder sb = new StringBuilder();
+
+    if (parameter.isPositionalContainer()) sb.append("*");
+    else if (parameter.isKeywordContainer()) sb.append("**");
+
+    final String name = parameter.getName();
+    sb.append(name != null ? name : "...");
+
+    return sb.toString();
+  }
+
+  /**
+   * @param defaultValue             string returned by {@link PyCallableParameter#getDefaultValueText()} or {@link PyParameter#getDefaultValueText()}.
+   * @param parameterRenderedAsTyped true if parameter is rendered with type annotation.
+   * @return equal sign (surrounded with spaces if {@code parameterRenderedAsTyped}) +
+   * {@code defaultValue} (with body escaped if it is a string literal)
+   */
+  @Nullable
+  @Contract("null, _->null")
+  public static String getDefaultValuePartInSignature(@Nullable String defaultValue, boolean parameterRenderedAsTyped) {
+    if (defaultValue == null) return null;
+
+    final StringBuilder sb = new StringBuilder();
+
+    // According to PEP 8 equal sign should be surrounded by spaces if annotation is present
+    sb.append(parameterRenderedAsTyped ? " = " : "=");
+
+    final Pair<String, String> quotes = PyStringLiteralCoreUtil.getQuotes(defaultValue);
+    if (quotes != null) {
+      final String value = defaultValue.substring(quotes.getFirst().length(), defaultValue.length() - quotes.getSecond().length());
+      sb.append(quotes.getFirst());
+      StringUtil.escapeStringCharacters(value.length(), value, sb);
+      sb.append(quotes.getSecond());
+    }
+    else {
+      sb.append(defaultValue);
+    }
+
+    return sb.toString();
+  }
+
   /**
    * @param defaultValue expression returned by {@link PyCallableParameter#getDefaultValue()} or {@link PyParameter#getDefaultValue()}.
    * @return {@code defaultValue} value surrounded by quotes if it is a multi-line string literal, {@code defaultValue} text otherwise.
diff --git a/python/python-psi-api/src/com/jetbrains/python/psi/PyNamedParameter.java b/python/python-psi-api/src/com/jetbrains/python/psi/PyNamedParameter.java
index 56d1e8843c30..e05150976303 100644
--- a/python/python-psi-api/src/com/jetbrains/python/psi/PyNamedParameter.java
+++ b/python/python-psi-api/src/com/jetbrains/python/psi/PyNamedParameter.java
@@ -38,17 +38,6 @@ public interface PyNamedParameter extends PyAstNamedParameter, PyParameter, PsiN
     return (PyExpression)PyAstNamedParameter.super.getDefaultValue();
   }
 
-  /**
-   * @param includeDefaultValue if true, include the default value after an "=".
-   * @return canonical representation of parameter.
-   * Includes asterisks for *param and **param, and name.
-   */
-  @Override
-  @NotNull
-  default String getRepr(boolean includeDefaultValue) {
-    return getRepr(includeDefaultValue, null);
-  }
-
   /**
    * @param includeDefaultValue if true, include the default value after an "=".
    * @param context             context to be used to resolve argument type
diff --git a/python/python-psi-impl/src/com/jetbrains/python/psi/impl/ParamHelper.java b/python/python-psi-impl/src/com/jetbrains/python/psi/impl/ParamHelper.java
index ac43b62f6a06..5e702715af86 100644
--- a/python/python-psi-impl/src/com/jetbrains/python/psi/impl/ParamHelper.java
+++ b/python/python-psi-impl/src/com/jetbrains/python/psi/impl/ParamHelper.java
@@ -15,10 +15,9 @@
  */
 package com.jetbrains.python.psi.impl;
 
-import com.intellij.openapi.util.Pair;
-import com.intellij.openapi.util.text.StringUtil;
 import com.intellij.psi.PsiElement;
 import com.intellij.util.containers.ContainerUtil;
+import com.jetbrains.python.ast.impl.ParamHelperCore;
 import com.jetbrains.python.psi.*;
 import com.jetbrains.python.psi.types.PyCallableParameter;
 import com.jetbrains.python.psi.types.PyCallableParameterImpl;
@@ -148,15 +147,7 @@ public final class ParamHelper {
 
   @NotNull
   public static String getNameInSignature(@NotNull PyNamedParameter parameter) {
-    final StringBuilder sb = new StringBuilder();
-
-    if (parameter.isPositionalContainer()) sb.append("*");
-    else if (parameter.isKeywordContainer()) sb.append("**");
-
-    final String name = parameter.getName();
-    sb.append(name != null ? name : "...");
-
-    return sb.toString();
+    return ParamHelperCore.getNameInSignature(parameter);
   }
 
   /**
@@ -168,25 +159,7 @@ public final class ParamHelper {
   @Nullable
   @Contract("null, _->null")
   public static String getDefaultValuePartInSignature(@Nullable String defaultValue, boolean parameterRenderedAsTyped) {
-    if (defaultValue == null) return null;
-
-    final StringBuilder sb = new StringBuilder();
-
-    // According to PEP 8 equal sign should be surrounded by spaces if annotation is present
-    sb.append(parameterRenderedAsTyped ? " = " : "=");
-
-    final Pair<String, String> quotes = PyStringLiteralCoreUtil.getQuotes(defaultValue);
-    if (quotes != null) {
-      final String value = defaultValue.substring(quotes.getFirst().length(), defaultValue.length() - quotes.getSecond().length());
-      sb.append(quotes.getFirst());
-      StringUtil.escapeStringCharacters(value.length(), value, sb);
-      sb.append(quotes.getSecond());
-    }
-    else {
-      sb.append(defaultValue);
-    }
-
-    return sb.toString();
+    return ParamHelperCore.getDefaultValuePartInSignature(defaultValue, parameterRenderedAsTyped);
   }
 
   public static boolean couldHaveDefaultValue(@NotNull String parameterName) {