code: public StatementBuilder withQualifierValue(PropertyIdValue propertyIdValue,
  			Value value) {
  		withQualifier(factory.getValueSnak(propertyIdValue, value));
  		return getThis();
  	}
docs: Adds a qualifier with the given property and value to the constructed
  statement.
  
  @param propertyIdValue
  the property of the qualifier
  @param value
  the value of the qualifier
  @return builder object to continue construction