extract interface from PyClassType

python/psi-api/src/com/jetbrains/python/psi/types/PyCallableType.java

@@ -0,0 +1,23 @@
+package com.jetbrains.python.psi.types;
+
+import com.jetbrains.python.psi.PyQualifiedExpression;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+/**
+ * A type instances of which can possibly be called. For example, a class definition can be called, and the result of a call is a class
+ * instance.
+ *
+ * @author yole
+ */
+public interface PyCallableType extends PyType {
+  /**
+   * Returns the type which is the result of calling an instance of this type.
+   *
+   * @return the call result type or null if invalid.
+   * @param context
+   * @param callSite
+   */
+  @Nullable
+  PyType getCallType(@NotNull TypeEvalContext context, @Nullable PyQualifiedExpression callSite);
+}

python/psi-api/src/com/jetbrains/python/psi/types/PyClassType.java

@@ -0,0 +1,22 @@
+package com.jetbrains.python.psi.types;
+
+import com.intellij.openapi.util.UserDataHolder;
+import com.jetbrains.python.psi.PyClass;
+import org.jetbrains.annotations.Nullable;
+
+/**
+ * @author yole
+ */
+public interface PyClassType extends PyCallableType, UserDataHolder {
+  @Nullable
+  PyClass getPyClass();
+
+  boolean isDefinition();
+
+  PyClassType toInstance();
+
+  @Nullable
+  String getClassQName();
+
+  boolean isValid();
+}