docs: public static ASN1Sequence getInstance(
          ASN1TaggedObject    obj,
          boolean             explicit)
      {
          if (explicit)
          {
              if (!obj.isExplicit())
              {
                  throw new IllegalArgumentException("object implicit - explicit expected.");
              }
  
              return (ASN1Sequence)obj.getObject();
          }
          else
          {
              //
              // constructed object which appears to be explicitly tagged
              // when it should be implicit means we have to add the
              // surrounding sequence.
              //
              if (obj.isExplicit())
              {
                  if (obj instanceof BERTaggedObject)
                  {
                      return new BERSequence(obj.getObject());
                  }
                  else
                  {
                      return new DERSequence(obj.getObject());
                  }
              }
              else
              {
                  if (obj.getObject() instanceof ASN1Sequence)
                  {
                      return (ASN1Sequence)obj.getObject();
                  }
              }
          }
  
          throw new IllegalArgumentException(
                  "unknown object in getInstanceFromTagged");
      }