https://www.graalvm.org/ 
final class com.oracle.truffle.llvm.tests.interop.PyObjectTest$MemberMatcher extends org.hamcrest.TypeSafeMatcher<org.graalvm.polyglot.Value>
  minor version: 0
  major version: 59
  flags: flags: (0x0030) ACC_FINAL, ACC_SUPER
  this_class: com.oracle.truffle.llvm.tests.interop.PyObjectTest$MemberMatcher
  super_class: org.hamcrest.TypeSafeMatcher
{
  private final java.lang.String name;
    descriptor: Ljava/lang/String;
    flags: (0x0012) ACC_PRIVATE, ACC_FINAL

  private final org.hamcrest.TypeSafeMatcher<org.graalvm.polyglot.Value> matcher;
    descriptor: Lorg/hamcrest/TypeSafeMatcher;
    flags: (0x0012) ACC_PRIVATE, ACC_FINAL
    Signature: Lorg/hamcrest/TypeSafeMatcher<Lorg/graalvm/polyglot/Value;>;

  final com.oracle.truffle.llvm.tests.interop.PyObjectTest this$0;
    descriptor: Lcom/oracle/truffle/llvm/tests/interop/PyObjectTest;
    flags: (0x1010) ACC_FINAL, ACC_SYNTHETIC

  void <init>(java.lang.String, org.hamcrest.TypeSafeMatcher<org.graalvm.polyglot.Value>);
    descriptor: (Lcom/oracle/truffle/llvm/tests/interop/PyObjectTest;Ljava/lang/String;Lorg/hamcrest/TypeSafeMatcher;)V
    flags: (0x0000) 
    Code:
      stack=2, locals=4, args_size=4
        start local 0 // com.oracle.truffle.llvm.tests.interop.PyObjectTest$MemberMatcher this
        start local 2 // java.lang.String name
        start local 3 // org.hamcrest.TypeSafeMatcher matcher
         0: .line 83
            aload 0 /* this */
            aload 1
            putfield com.oracle.truffle.llvm.tests.interop.PyObjectTest$MemberMatcher.this$0:Lcom/oracle/truffle/llvm/tests/interop/PyObjectTest;
         1: .line 84
            aload 0 /* this */
            ldc Lorg/graalvm/polyglot/Value;
            invokespecial org.hamcrest.TypeSafeMatcher.<init>:(Ljava/lang/Class;)V
         2: .line 85
            aload 0 /* this */
            aload 2 /* name */
            putfield com.oracle.truffle.llvm.tests.interop.PyObjectTest$MemberMatcher.name:Ljava/lang/String;
         3: .line 86
            aload 0 /* this */
            aload 3 /* matcher */
            putfield com.oracle.truffle.llvm.tests.interop.PyObjectTest$MemberMatcher.matcher:Lorg/hamcrest/TypeSafeMatcher;
         4: .line 87
            return
        end local 3 // org.hamcrest.TypeSafeMatcher matcher
        end local 2 // java.lang.String name
        end local 0 // com.oracle.truffle.llvm.tests.interop.PyObjectTest$MemberMatcher this
      LocalVariableTable:
        Start  End  Slot     Name  Signature
            0    5     0     this  Lcom/oracle/truffle/llvm/tests/interop/PyObjectTest$MemberMatcher;
            0    5     2     name  Ljava/lang/String;
            0    5     3  matcher  Lorg/hamcrest/TypeSafeMatcher<Lorg/graalvm/polyglot/Value;>;
    Signature: (Ljava/lang/String;Lorg/hamcrest/TypeSafeMatcher<Lorg/graalvm/polyglot/Value;>;)V
    MethodParameters:
         Name  Flags
      this$0   final
      name     
      matcher  

  protected boolean matchesSafely(org.graalvm.polyglot.Value);
    descriptor: (Lorg/graalvm/polyglot/Value;)Z
    flags: (0x0004) ACC_PROTECTED
    Code:
      stack=3, locals=2, args_size=2
        start local 0 // com.oracle.truffle.llvm.tests.interop.PyObjectTest$MemberMatcher this
        start local 1 // org.graalvm.polyglot.Value item
         0: .line 91
            aload 1 /* item */
            aload 0 /* this */
            getfield com.oracle.truffle.llvm.tests.interop.PyObjectTest$MemberMatcher.name:Ljava/lang/String;
            invokevirtual org.graalvm.polyglot.Value.hasMember:(Ljava/lang/String;)Z
            ifeq 2
         1: .line 92
            aload 0 /* this */
            getfield com.oracle.truffle.llvm.tests.interop.PyObjectTest$MemberMatcher.matcher:Lorg/hamcrest/TypeSafeMatcher;
            aload 1 /* item */
            aload 0 /* this */
            getfield com.oracle.truffle.llvm.tests.interop.PyObjectTest$MemberMatcher.name:Ljava/lang/String;
            invokevirtual org.graalvm.polyglot.Value.getMember:(Ljava/lang/String;)Lorg/graalvm/polyglot/Value;
            invokevirtual org.hamcrest.TypeSafeMatcher.matches:(Ljava/lang/Object;)Z
            ireturn
         2: .line 94
      StackMap locals:
      StackMap stack:
            iconst_0
            ireturn
        end local 1 // org.graalvm.polyglot.Value item
        end local 0 // com.oracle.truffle.llvm.tests.interop.PyObjectTest$MemberMatcher this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    3     0  this  Lcom/oracle/truffle/llvm/tests/interop/PyObjectTest$MemberMatcher;
            0    3     1  item  Lorg/graalvm/polyglot/Value;
    MethodParameters:
      Name  Flags
      item  

  public void describeTo(org.hamcrest.Description);
    descriptor: (Lorg/hamcrest/Description;)V
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=2, locals=2, args_size=2
        start local 0 // com.oracle.truffle.llvm.tests.interop.PyObjectTest$MemberMatcher this
        start local 1 // org.hamcrest.Description description
         0: .line 100
            aload 1 /* description */
            ldc "member "
            invokeinterface org.hamcrest.Description.appendText:(Ljava/lang/String;)Lorg/hamcrest/Description;
            aload 0 /* this */
            getfield com.oracle.truffle.llvm.tests.interop.PyObjectTest$MemberMatcher.name:Ljava/lang/String;
            invokeinterface org.hamcrest.Description.appendText:(Ljava/lang/String;)Lorg/hamcrest/Description;
            ldc " is "
            invokeinterface org.hamcrest.Description.appendText:(Ljava/lang/String;)Lorg/hamcrest/Description;
            aload 0 /* this */
            getfield com.oracle.truffle.llvm.tests.interop.PyObjectTest$MemberMatcher.matcher:Lorg/hamcrest/TypeSafeMatcher;
            invokeinterface org.hamcrest.Description.appendDescriptionOf:(Lorg/hamcrest/SelfDescribing;)Lorg/hamcrest/Description;
            pop
         1: .line 101
            return
        end local 1 // org.hamcrest.Description description
        end local 0 // com.oracle.truffle.llvm.tests.interop.PyObjectTest$MemberMatcher this
      LocalVariableTable:
        Start  End  Slot         Name  Signature
            0    2     0         this  Lcom/oracle/truffle/llvm/tests/interop/PyObjectTest$MemberMatcher;
            0    2     1  description  Lorg/hamcrest/Description;
    MethodParameters:
             Name  Flags
      description  

  protected void describeMismatchSafely(org.graalvm.polyglot.Value, org.hamcrest.Description);
    descriptor: (Lorg/graalvm/polyglot/Value;Lorg/hamcrest/Description;)V
    flags: (0x0004) ACC_PROTECTED
    Code:
      stack=3, locals=3, args_size=3
        start local 0 // com.oracle.truffle.llvm.tests.interop.PyObjectTest$MemberMatcher this
        start local 1 // org.graalvm.polyglot.Value item
        start local 2 // org.hamcrest.Description description
         0: .line 105
            aload 1 /* item */
            aload 0 /* this */
            getfield com.oracle.truffle.llvm.tests.interop.PyObjectTest$MemberMatcher.name:Ljava/lang/String;
            invokevirtual org.graalvm.polyglot.Value.hasMember:(Ljava/lang/String;)Z
            ifeq 4
         1: .line 106
            aload 2 /* description */
            aload 0 /* this */
            getfield com.oracle.truffle.llvm.tests.interop.PyObjectTest$MemberMatcher.name:Ljava/lang/String;
            invokeinterface org.hamcrest.Description.appendText:(Ljava/lang/String;)Lorg/hamcrest/Description;
            ldc " "
            invokeinterface org.hamcrest.Description.appendText:(Ljava/lang/String;)Lorg/hamcrest/Description;
            pop
         2: .line 107
            aload 0 /* this */
            getfield com.oracle.truffle.llvm.tests.interop.PyObjectTest$MemberMatcher.matcher:Lorg/hamcrest/TypeSafeMatcher;
            aload 1 /* item */
            aload 0 /* this */
            getfield com.oracle.truffle.llvm.tests.interop.PyObjectTest$MemberMatcher.name:Ljava/lang/String;
            invokevirtual org.graalvm.polyglot.Value.getMember:(Ljava/lang/String;)Lorg/graalvm/polyglot/Value;
            aload 2 /* description */
            invokevirtual org.hamcrest.TypeSafeMatcher.describeMismatch:(Ljava/lang/Object;Lorg/hamcrest/Description;)V
         3: .line 108
            goto 5
         4: .line 109
      StackMap locals:
      StackMap stack:
            aload 2 /* description */
            ldc "has no member "
            invokeinterface org.hamcrest.Description.appendText:(Ljava/lang/String;)Lorg/hamcrest/Description;
            aload 0 /* this */
            getfield com.oracle.truffle.llvm.tests.interop.PyObjectTest$MemberMatcher.name:Ljava/lang/String;
            invokeinterface org.hamcrest.Description.appendText:(Ljava/lang/String;)Lorg/hamcrest/Description;
            pop
         5: .line 111
      StackMap locals:
      StackMap stack:
            return
        end local 2 // org.hamcrest.Description description
        end local 1 // org.graalvm.polyglot.Value item
        end local 0 // com.oracle.truffle.llvm.tests.interop.PyObjectTest$MemberMatcher this
      LocalVariableTable:
        Start  End  Slot         Name  Signature
            0    6     0         this  Lcom/oracle/truffle/llvm/tests/interop/PyObjectTest$MemberMatcher;
            0    6     1         item  Lorg/graalvm/polyglot/Value;
            0    6     2  description  Lorg/hamcrest/Description;
    MethodParameters:
             Name  Flags
      item         
      description  

  protected boolean matchesSafely(java.lang.Object);
    descriptor: (Ljava/lang/Object;)Z
    flags: (0x1044) ACC_PROTECTED, ACC_BRIDGE, ACC_SYNTHETIC
    Code:
      stack=2, locals=2, args_size=2
         0: .line 1
            aload 0
            aload 1
            checkcast org.graalvm.polyglot.Value
            invokevirtual com.oracle.truffle.llvm.tests.interop.PyObjectTest$MemberMatcher.matchesSafely:(Lorg/graalvm/polyglot/Value;)Z
            ireturn
      LocalVariableTable:
        Start  End  Slot  Name  Signature

  protected void describeMismatchSafely(java.lang.Object, org.hamcrest.Description);
    descriptor: (Ljava/lang/Object;Lorg/hamcrest/Description;)V
    flags: (0x1044) ACC_PROTECTED, ACC_BRIDGE, ACC_SYNTHETIC
    Code:
      stack=3, locals=3, args_size=3
         0: .line 1
            aload 0
            aload 1
            checkcast org.graalvm.polyglot.Value
            aload 2
            invokevirtual com.oracle.truffle.llvm.tests.interop.PyObjectTest$MemberMatcher.describeMismatchSafely:(Lorg/graalvm/polyglot/Value;Lorg/hamcrest/Description;)V
            return
      LocalVariableTable:
        Start  End  Slot  Name  Signature
}
Signature: Lorg/hamcrest/TypeSafeMatcher<Lorg/graalvm/polyglot/Value;>;
SourceFile: "PyObjectTest.java"
NestHost: com.oracle.truffle.llvm.tests.interop.PyObjectTest
InnerClasses:
  final MemberMatcher = com.oracle.truffle.llvm.tests.interop.PyObjectTest$MemberMatcher of com.oracle.truffle.llvm.tests.interop.PyObjectTest