Time.Date.to_z.at: def of bend-kit-time@0.3.0.0
Import: import bend-kit-time@0.3.0.0/time.bend as Time
Lines 209-213 of bend-kit-time@0.3.0.0/time.bend: https://jend.leeeet.dev/read.txt?path=bend-kit-time@0.3.0.0/time.bend&start_line=209&end_line=213

import Base

def Date.to_z.at(+y: U32, +mp: U32, +d: U32) -> U32:
  +era = (y / 400 : U32)
  +yoe = (y - era * 400 : U32)
  +doy = ((153 * mp + 2) / 5 + d - 1 : U32)
  (era * 146097 + yoe * 365 + yoe / 4 - yoe / 100 + doy : U32)

Uses (5):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=U32
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=U32.add
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=U32.div
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=U32.mul
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=U32.sub