message: Give more helpful error when toco_from_protos binary is not found.
diff: @@ -19,6 +19,7 @@ from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  +import distutils.spawn
  import enum # pylint: disable=g-bad-import-order
  import os as _os
  import platform as _platform
  @@ -136,6 +137,17 @@ def toco_convert_protos(model_flags_str,
  except Exception as e:
  raise ConverterError(str(e))
  + if distutils.spawn.find_executable(_toco_from_proto_bin) is None:
  + raise ConverterError("""Could not find toco_from_protos binary, make sure
  +your virtualenv bin directory or pip local bin directory is in your path.
  +In particular, if you have installed TensorFlow with --user, make sure you
  +add the install directory to your path.
  +
  +For example:
  +Linux: export PATH=$PATH:~/.local/bin/
  +Mac: export PATH=$PATH:~/Library/Python/<version#>/bin
  +
  +Alternative, use virtualenv.""")
  # Windows and TemporaryFile are not that useful together,
  # since you cannot have two readers/writers. So we have to
  # make the temporaries and close and delete them explicitly.
  