code: def beamcenterx(self) -> ErrorValue:
          
          try:
              return ErrorValue(self._data['geometry']['beamposy'],
                                self._data['geometry']['beamposy.err'])
          except KeyError:
              return ErrorValue(self._data['geometry']['beamposy'],
                                0.0)
docs: X (column) coordinate of the beam center, pixel units, 0-based.