It appears as if the use of IrrigationManagment within AquaCropModel requires the importation of IrrigationManagement from aquacrop. It was necessary to modify the first import line to: from aquacrop import AquaCropModel, Soil, Crop, InitialWaterContent, IrrigationManagement, rather than only what was done in Notebook 1.
In the tutorial at https://colab.research.google.com/github/aquacropos/aquacrop/blob/master/docs/notebooks/AquaCrop_OSPy_Notebook_2.ipynb#scrollTo=w4OIG8Y1VSXx, Notebook 2, Irrigation Management:
It appears as if the use of IrrigationManagment within AquaCropModel requires the importation of IrrigationManagement from aquacrop. It was necessary to modify the first import line to: from aquacrop import AquaCropModel, Soil, Crop, InitialWaterContent, IrrigationManagement, rather than only what was done in Notebook 1.