class_docstr: A collection of functions to be tested
code: def func_reduction_mix_axis_0(be, x0, x1, x2, x3):
      f1 = be.mean(x0, axis=0, keepdims=True)
      f2 = be.max(x1, axis=0, keepdims=True) + be.min(
          x1, axis=0, keepdims=True
      )
      f3 = be.std(x2, keepdims=True)
      if be is np:
          f4 = be.argmax(x3, axis=0).reshape(-1, x3.shape[1])
      else:
          f4 = be.argmax(x3, axis=0, keepdims=True)
      x4 = be.empty((4, x0.shape[1]))
      x4[0, :] = f1
      x4[1, :] = f2
      x4[2, :] = f3
      x4[3, :] = f4
      return x4
  
file_path: neon/tests/test_backend_reduction.py
imports: import itertools
  import numpy
  import pytest
  from neon import NervanaObject
  from utils import call_func, gen_backend_tensors, tensors_allclose
label_desc: Use image node_id 1 for calling the TestFuncs obj's underlying member method code with example usage: obj.func_reduction_mix_axis_0(be, x0, x1, x2, x3) and returns: x4