class_docstr: Test common dtype coercion rules between concat and append.
class_docstr_tok: ["Test","common","dtype","coercion","rules","between","concat","and","append","."]
code: def test_concatlike_common_period(self):
      # GH 13660
      pi1 = pd.PeriodIndex(["2011-01", "2011-02"], freq="M")
      pi2 = pd.PeriodIndex(["2012-01", "2012-02"], freq="M")
  
      exp = pd.PeriodIndex(
          ["2011-01", "2011-02", "2012-01", "2012-02"], freq="M"
      )
  
      res = pi1.append(pi2)
      tm.assert_index_equal(res, exp)
  
      ps1 = Series(pi1)
      ps2 = Series(pi2)
      res = ps1._append(ps2)
      tm.assert_series_equal(res, Series(exp, index=[0, 1, 0, 1]))
  
      res = pd.concat([ps1, ps2])
      tm.assert_series_equal(res, Series(exp, index=[0, 1, 0, 1]))
  
imports: import numpy
  import pytest
  import pandas
  from pandas import Categorical, DataFrame, Index, Series
  import pandas._testing
label_desc: Use image node_id 8 for calling the TestConcatAppendCommon obj's underlying member method code with example usage: obj.test_concatlike_common_period() without return types