code: def test_map_ignores_missing_value(self, missing):
      data = np.array([missing, "B", "C"], dtype=object)
      la = LabelArray(data, missing_value=missing)
  
      def increment_char(c):
          return chr(ord(c) + 1)
  
      result = la.map(increment_char)
      expected = LabelArray([missing, "C", "D"], missing_value=missing)
      assert_equal(result.as_string_array(), expected.as_string_array())
  
imports: from itertools import product
  from operator import eq, ne
  import warnings
  import numpy
  from toolz import take
  from zipline.lib.labelarray import LabelArray
  from zipline.testing import check_arrays, parameter_space, ZiplineTestCase
  from zipline.testing.predicates import assert_equal
  from zipline.utils.compat import unicode
label_desc: Use image node_id 5 for calling the LabelArrayTestCase obj's underlying member method code with example usage: obj.test_map_ignores_missing_value(missing) and returns: chr