$ cargo r -- "requests>2.2" "requests<2.1"
    Finished dev [unoptimized + debuginfo] target(s) in 0.07s
     Running `target/debug/rip 'requests>2.2' 'requests<2.1'`
  × Could not solve for the requested requirements:
  │ The following packages are incompatible
  │ |-- requests < 2.1 can be installed with any of the following options:
  │     |-- requests 2.0.1
  │     |-- requests 2.0.0
  │ |-- requests > 2.2 cannot be installed because there are no viable options:
  │     |-- requests 2.2.1 | 2.3.0 | 2.4.0 | 2.4.1 | 2.4.2 | 2.4.3 | 2.5.0 | 2.5.1 | 2.5.2 | 2.5.3 | 2.6.0 | 2.6.1 | 2.6.2 | 2.7.0 | 2.8.0 | 2.8.1 | 2.9.0 | 2.9.1 | 2.9.2 | 2.10.0 | 2.11.0 | 2.11.1 | 2.12.0 | 2.12.1 | 2.12.2 | 2.12.3 | 2.12.4 | 2.12.5 | 2.13.0 | 2.14.0 | 2.14.1 | 2.14.2 | 2.15.1 | 2.16.0 | 2.16.1
  │ | 2.16.2 | 2.16.3 | 2.16.4 | 2.16.5 | 2.17.0 | 2.17.1 | 2.17.2 | 2.17.3 | 2.18.0 | 2.18.1 | 2.18.2 | 2.18.3 | 2.18.4 | 2.19.0 | 2.19.1 | 2.20.0 | 2.20.1 | 2.21.0 | 2.22.0 | 2.23.0 | 2.24.0 | 2.25.0 | 2.25.1 | 2.26.0 | 2.27.0 | 2.27.1 | 2.28.0 | 2.28.1 | 2.28.2 | 2.29.0 | 2.30.0 | 2.31.0, which conflicts with
  │ the versions reported above.
  │