in chartify/_core/axes.py [0:0]
def _convert_major_orientation_labels(orientation):
"""Map the user inputted orientation values to the values expected by
bokeh for major labels."""
if orientation == "vertical":
orientation = pi / 180 * 90
elif orientation == "diagonal":
orientation = pi / 180 * 45
elif orientation != "horizontal":
raise ValueError("Orientation must be `horizontal`, `vertical`, or `diagonal`.")
return orientation