Proguard doesn't keep access modifier in parameterized constructor

Question

I have following class A

Class A {

  public A(String param1, String param2)
   // body
  }

  public A(String param1, String param2, String param3)
   // body
  }
}

My proguard settings

keep 'public class com.test.A$* {  public *;}'
keepclassmembers 'class * extends com.test.A { public <init>(...);}'

After obsfucation, Class A look like below, Access modifier is changed from public to private. How can I keep the access modifier?

Class A {

  private A(String var1, String var2)
   // body
  }

  private A(String var1, String var2, String var3)
   // body
  }
}