| check_data | Data Checking Function | 
| circ_mle | circ_mle | 
| ci_circmle | ci_circmle | 
| dcor.circular | circular distance correlation function | 
| HR_test | Hermans-Rasson test function | 
| lr_test | Likelihood ratio test for nested models | 
| M1 | Model M1 MLE function | 
| M2A | Model M2A MLE function | 
| M2B | Model M2B MLE function | 
| M2C | Model M2C MLE function | 
| M3A | Model M3A MLE function | 
| M3B | Model M3B MLE function | 
| M4A | Model M4A MLE function | 
| M4B | Model M4B MLE function | 
| M5A | Model M5A MLE function | 
| M5B | Model M5B MLE function | 
| plot_circMLE | plot_circMLE | 
| pycke_test | Pycke test function |