title: DLDT (OpenVINO) install on Ubuntu 18.04 on Raspberry Pi 4 - Cython code error
body: <p>I am trying to install the DLDT package on Ubuntu 18.04 running on the Raspberry Pi 4. The 2019 branch of DLDT seems to install correctly with some issues but can be rectified. However, the later version (i.e. 2020.3) is giving me the below error:</p>
  <pre><code>Error compiling Cython file:
  ------------------------------------------------------------
  ...
      #  Usage example:\n
      #  ```python
      #  ie = IECore()
      #  net = ie.read_network(model=path_to_xml_file, weights=path_to_bin_file)
      #  ```
      cpdef IENetwork read_network(self, model: [str, bytes], weights: [str, bytes] = &quot;&quot;, init_from_buffer: bool = &quot;False&quot;):
           ^
  ------------------------------------------------------------
  
  /home/ubuntu/dldt/inference-engine/ie_bridges/python/src/openvino/inference_engine/ie_api.pyx:136:10: Signature not compatible with previous declaration
  
  Error compiling Cython file:
  ------------------------------------------------------------
  ...
  cdef class LayersStatsMap(dict):
      cdef C.IENetwork net_impl
  
  cdef class IECore:
      cdef C.IECore impl
      cpdef IENetwork read_network(self, model : [str, bytes], weights : [str, bytes] = ?, bool init_from_buffer = ?)
                                 ^
  ------------------------------------------------------------
  
  </code></pre>
  <p>The CMAKE command I use is:</p>
  <pre><code>sudo cmake -DCMAKE_BUILD_TYPE=Release -DENABLE_MKL_DNN=OFF -DENABLE_CLDNN=OFF -DENABLE_GNA=OFF -DENABLE_SSE42=OFF -DTHREADING=SEQ -DENABLE_OPENCV=OFF -DENABLE_PYTHON=ON -DPYTHON_EXECUTABLE=/usr/bin/python3.6 -DPYTHON_LIBRARY=/usr/lib/aarch64-linux-gnu/libpython3.6m.so -DPYTHON_INCLUDE_DIR=/usr/include/python3.6 ..
  </code></pre>
  <p>It seems like there is an issue with the declaration of the function or the usage of it. Is there any advice on this from anybody?</p>
  <p>Is this a compatibility issue? Is this related to some Cython version issues? The one I have is: 0.29.21</p>
  <p>Would appreciate some help on this. Thanks in advance!</p>