root:
             creates   file:./
             creates   file:plan.py
             creates   step:runpy ./plan.py

file:./
               state = STATIC
          created by   root:
            supplies   file:cat.pdf
            supplies   file:doc1.pdf
            supplies   file:doc2.pdf
            supplies   file:plan.py
            supplies   step:cat-pdf doc1.pdf doc2.pdf cat.pdf
            supplies   step:runpy ./plan.py

file:plan.py
               state = STATIC
          created by   root:
            consumes   file:./
            supplies   step:runpy ./plan.py

step:runpy ./plan.py
               state = SUCCEEDED
             env_var = STEPUP_PATH_FILTER [amended]
          created by   root:
            consumes   file:./
            consumes   file:plan.py
             creates   file:doc1.pdf
             creates   file:doc2.pdf
             creates   step:cat-pdf doc1.pdf doc2.pdf cat.pdf

file:doc1.pdf
               state = STATIC
          created by   step:runpy ./plan.py
            consumes   file:./
            supplies   step:cat-pdf doc1.pdf doc2.pdf cat.pdf

file:doc2.pdf
               state = STATIC
          created by   step:runpy ./plan.py
            consumes   file:./
            supplies   step:cat-pdf doc1.pdf doc2.pdf cat.pdf

step:cat-pdf doc1.pdf doc2.pdf cat.pdf
               state = SUCCEEDED
          created by   step:runpy ./plan.py
            consumes   file:./
            consumes   file:doc1.pdf
            consumes   file:doc2.pdf
             creates   file:cat.pdf
            supplies   file:cat.pdf

file:cat.pdf
               state = BUILT
          created by   step:cat-pdf doc1.pdf doc2.pdf cat.pdf
            consumes   file:./
            consumes   step:cat-pdf doc1.pdf doc2.pdf cat.pdf
