Raster function with condtional function

Question

I have two raster layers and a function sand.tif, clay.tif and def soiltexturalclass(sand,clay):. The function is a conditional function which can be viewed here.

The goal is to create an output raster from the result of the function. I was able to write a function that successfully creates a new array from my function. When trying to run the below function though, I receive a blank raster.

IE outras = soiltexturalclass(sand.tif,clay.tif)

import numpy as np

class SoilTexture():

    def __init__(self):
        self.name = "NRCS Soil Texture Classification"
        self.description = "Computes soil texture given clay and sand content."
        
    def getParameterInfo(self):
        return [
            { 
                'name': 'Clay',
                'dataType': 'raster',
                'value': None,
                'required': True,
                'displayName': "Clay %",
                'description': "Single-band raster where pixel values represent clay content in mass/mass."
            },
            {
                'name': 'Sand',
                'dataType': 'raster',
                'value': None,
                'required': True,
                'displayName': "Sand %",
                'description': "Single-band raster where pixel values represent sand content in mass/mass."
            },
        ]
    
    def getConfiguration(self, **scalars):
        return {
            'inheritProperties': 2 | 4 | 8,     # inherit all but the pixel type from the input raster
            'invalidateProperties': 2 | 4 | 8,  # reset any statistics and histogram that might be held by
                                                #   the parent dataset (because this function modifies pixel values).
            'inputMask': True                   # We need the input raster mask in .updatePixels().
        }

    def updateRasterInfo(self, **kwargs):
        kwargs['output_info']['bandCount'] = 1
        kwargs['output_info']['pixelType'] = 'u1'
        kwargs['output_info']['statistics'] = ()
        kwargs['output_info']['noData'] = np.array([0], 'u1')
        return kwargs

    def updatePixels(self, tlc, shape, props, **pixelBlocks):

        sand = np.array(pixelBlocks['sand_pixels'], dtype='f4', copy=False)
        clay = np.array(pixelBlocks['clay_pixels'], dtype='f4', copy=False)

        sand = sand/10
        clay = clay/10
        silt = (100 - sand - clay).astype('f4', copy=False)
        def TextureClass(sand, clay, silt):
    
        #if sand + clay > 100 or sand < 0 or clay < 0:
        #    raise Exception('Inputs adds over 100% or are negative')

            if silt + 1.5*clay < 15:
                textural_class = 'sand'

            elif silt + 1.5*clay >= 15 and silt + 2*clay < 30:
                textural_class = 'loamy sand'

            elif (clay >= 7 and clay < 20 and sand > 52 and silt + 2*clay >= 30) or (clay < 7 and silt < 50 and silt + 2*clay >= 30):
                textural_class = 'sandy loam'

            elif clay >= 7 and clay < 27 and silt >= 28 and silt < 50 and sand <= 52:
                textural_class = 'loam'

            elif (silt >= 50 and clay >= 12 and clay < 27) or (silt >= 50 and silt < 80 and clay < 12):
                textural_class = 'silt loam'

            elif silt >= 80 and clay < 12:
                textural_class = 'silt'

            elif clay >= 20 and clay < 35 and silt < 28 and sand > 45:
                textural_class = 'sandy clay loam'

            elif clay >= 27 and clay < 40 and sand > 20 and sand <= 45:
                textural_class = 'clay loam'

            elif clay >= 27 and clay < 40 and sand <= 20:
                textural_class = 'silty clay loam'

            elif clay >= 35 and sand > 45:
                textural_class = 'sandy clay'

            elif clay >= 40 and silt >= 40:
                textural_class = 'silty clay'

            elif clay >= 40 and sand <= 45 and silt < 40:
                textural_class = 'clay'

            else:
                textural_class = 'na'

            return textural_class

        vect_function = np.vectorize(TextureClass)

        pixelBlocks['output_pixels'] = vect_function(sand, clay, silt).astype(props['pixelType'], copy=False)
        return pixelBlocks