Here's sample code that worked in ArcMap, but I have not tested in Pro.
# standard python toolbox formatting for your utility toolbox
# C:/path/to/this/toolbox.pyt
class Toolbox(object):
def __init__(self):
self.label = 'your label'
self.alias = 'some_alias'
self.tools = [tool1, tool2, tool3]
# later on when you want to call them, e.g. from another .pyt
ImportToolbox(input_file='C:/path/to/this/toolbox.pyt')
arcpy.some_alias.tool1(arg1, arg2, ...)
arcpy.some_alias.tool2(arg1, ...)
arcpy.some_alias.tool3(arg1, ...)