Syntax warning cctbx

[picca]

Hello, I got these syntax warning during the installation of cctbx with dials

Paramétrage de python3-dials (2.2.1+dfsg2-1) ...
/usr/lib/python3/dist-packages/mmtbx/hydrogens/__init__.py:237: SyntaxWarning: "is not" with a literal. Did you mean "!="?
  if(len(result)>0 is not None): return result
/usr/lib/python3/dist-packages/mmtbx/hydrogens/__init__.py:284: SyntaxWarning: "is not" with a literal. Did you mean "!="?
  if(len(result)>0 is not None): return result
/usr/lib/python3/dist-packages/scitbx/matrix/__init__.py:1694: SyntaxWarning: "is" with a literal. Did you mean "=="?
  assert f(vector_1=col([0,0,0]), vector_2=col([0,0,0])) is 0
/usr/lib/python3/dist-packages/xfel/command_line/frame_extractor.py:174: SyntaxWarning: "is not" with a literal. Did you mean "!="?
  assert self.frame['xbeam'] is not 0 and self.frame['ybeam'] is not 0, "invalid beam center"
/usr/lib/python3/dist-packages/xfel/command_line/frame_extractor.py:174: SyntaxWarning: "is not" with a literal. Did you mean "!="?
  assert self.frame['xbeam'] is not 0 and self.frame['ybeam'] is not 0, "invalid beam center"
/usr/lib/python3/dist-packages/xfel/command_line/or_mask.py:27: SyntaxWarning: "is not" with a literal. Did you mean "!="?
  if dirname is not "" and not os.path.isdir(dirname):
/usr/lib/python3/dist-packages/xfel/cxi/cspad_ana/cspad_tbx.py:673: SyntaxWarning: "is not" with a literal. Did you mean "!="?
  if dirname is not "" and not os.path.isdir(dirname):
/usr/lib/python3/dist-packages/xfel/cxi/cxi_cc.py:252: SyntaxWarning: "is not" with a literal. Did you mean "!="?
  if reindexing_op is not "h,k,l":
/usr/lib/python3/dist-packages/xfel/merging/command_line/merge.py:61: SyntaxWarning: "is not" with a literal. Did you mean "!="?
  if diff_phil_str is not "":
Paramétrage de dials (2.2.1+dfsg2-1) ...

[Anthchirp]

Python 3.8 no longer tolerates misuse of is/is not and throws this SyntaxWarning. cctbx does not officially support 3.8 yet.

Feel free to submit a pull request