@Override
  public String format(final Schema schema) {
    final String converted = SchemaWalker.visit(schema, new Converter()) + typePostFix(schema);

    return options.contains(Option.AS_COLUMN_LIST)
        ? stripTopLevelStruct(converted)
        : converted;
  }
@Test
  public void shouldFormatMap() {
    // Given:
    final Schema schema = SchemaBuilder
        .map(Schema.STRING_SCHEMA, Schema.FLOAT64_SCHEMA)
        .build();

    // Then:
    assertThat(DEFAULT.format(schema),
        is("MAP<VARCHAR, DOUBLE>"));

    assertThat(STRICT.format(schema),
        is("MAP<VARCHAR NOT NULL, DOUBLE NOT NULL> NOT NULL"));
  }