Created temporary directory: /tmp/pip-ephem-wheel-cache-mq7r92jt
Created temporary directory: /tmp/pip-req-tracker-vql6mlud
Created requirements tracker '/tmp/pip-req-tracker-vql6mlud'
Created temporary directory: /tmp/pip-wheel-wue5hvqb
Collecting backcall==0.2.0
  1 location(s) to search for versions of backcall:
  * https://pypi.org/simple/backcall/
  Getting page https://pypi.org/simple/backcall/
  Analyzing links from page https://pypi.org/simple/backcall/
    Found link https://files.pythonhosted.org/packages/84/71/c8ca4f5bb1e08401b916c68003acf0a0655df935d74d93bf3f3364b310e0/backcall-0.1.0.tar.gz#sha256=38ecd85be2c1e78f77fd91700c76e14667dc21e2713b63876c0eb901196e01e4 (from https://pypi.org/simple/backcall/), version: 0.1.0
    Found link https://files.pythonhosted.org/packages/1b/b3/0708228132a772de8802967af71d00c6b1f2f407e6f8efcc7055ac5900fe/backcall-0.1.0.zip#sha256=bbbf4b1e5cd2bdb08f915895b51081c041bac22394fdfcfdfbe9f14b77c08bf2 (from https://pypi.org/simple/backcall/), version: 0.1.0
    Found link https://files.pythonhosted.org/packages/4c/1c/ff6546b6c12603d8dd1070aa3c3d273ad4c07f5771689a7b69a550e8c951/backcall-0.2.0-py2.py3-none-any.whl#sha256=fbbce6a29f263178a1f7915c1940bde0ec2b2a967566fe1c65c1dfb7422bd255 (from https://pypi.org/simple/backcall/), version: 0.2.0
    Found link https://files.pythonhosted.org/packages/a2/40/764a663805d84deee23043e1426a9175567db89c8b3287b5c2ad9f71aa93/backcall-0.2.0.tar.gz#sha256=5cbdbf27be5e7cfadb448baf0aa95508f91f2bbc6c6437cd9cd06e2a4c215e1e (from https://pypi.org/simple/backcall/), version: 0.2.0
  Using version 0.2.0 (newest of versions: 0.2.0)
  Created temporary directory: /tmp/pip-unpack-_ot7i4d2
  Downloading https://files.pythonhosted.org/packages/4c/1c/ff6546b6c12603d8dd1070aa3c3d273ad4c07f5771689a7b69a550e8c951/backcall-0.2.0-py2.py3-none-any.whl
  Downloading from URL https://files.pythonhosted.org/packages/4c/1c/ff6546b6c12603d8dd1070aa3c3d273ad4c07f5771689a7b69a550e8c951/backcall-0.2.0-py2.py3-none-any.whl#sha256=fbbce6a29f263178a1f7915c1940bde0ec2b2a967566fe1c65c1dfb7422bd255 (from https://pypi.org/simple/backcall/)
  Saved /tmp/tmp_jv2dngk/backcall-0.2.0-py2.py3-none-any.whl
  Added backcall==0.2.0 from https://files.pythonhosted.org/packages/4c/1c/ff6546b6c12603d8dd1070aa3c3d273ad4c07f5771689a7b69a550e8c951/backcall-0.2.0-py2.py3-none-any.whl#sha256=fbbce6a29f263178a1f7915c1940bde0ec2b2a967566fe1c65c1dfb7422bd255 to build tracker '/tmp/pip-req-tracker-vql6mlud'
  Removed backcall==0.2.0 from https://files.pythonhosted.org/packages/4c/1c/ff6546b6c12603d8dd1070aa3c3d273ad4c07f5771689a7b69a550e8c951/backcall-0.2.0-py2.py3-none-any.whl#sha256=fbbce6a29f263178a1f7915c1940bde0ec2b2a967566fe1c65c1dfb7422bd255 from build tracker '/tmp/pip-req-tracker-vql6mlud'
Skipping backcall, due to already being wheel.
Cleaning up...
  Removing source in /tmp/pip-wheel-wue5hvqb/backcall
Removed build tracker '/tmp/pip-req-tracker-vql6mlud'