Add some checks

[scarlehoff]

Added some checks for the input

[codecov]

Codecov Report

Merging #38 (118dc01) into master (124adf5) will not change coverage.
The diff coverage is 0.00%.

@@          Coverage Diff           @@
##           master     #38   +/-   ##
======================================
  Coverage    0.00%   0.00%           
======================================
  Files          14      15    +1     
  Lines        1319    1335   +16     
======================================
- Misses       1319    1335   +16     

Flag	Coverage Δ
unittests	0.00% <0.00%> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
src/pycompressor/compressing.py	0.00% <0.00%> (ø)
src/pycompressor/estimators.py	0.00% <0.00%> (ø)
src/pycompressor/__init__.py	0.00% <0.00%> (ø)

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 124adf5...118dc01. Read the comment docs.