B.2.1.27 Units and Dimensionals

conversionwrite	Create or update the conversion factors
	`None=`conversionwrite`(data-type:I,(D,D))`
	$\rightarrow$ Conversion values are: scale, offset
exponentswrite	Create or update the exponents
	`None=`exponentswrite`(data-type:I,(D,D,D,D,D))`
	$\rightarrow$ Exponents values are: Mass, Length, Time, Temperature, Angle.
conversionread	Get the conversion values
	`(D,D)=`conversionread`()`
	$\rightarrow$ See 'conversionwrite' remarks.
unitsread	Get the units under current node
	`(mass-u:S,length-u:S,time-u:S,temp-u:S,angle-u:S)=`unitsread`()`
	$\rightarrow$ See 'unitswrite' remarks.
dataclasswrite	Create or update the dataclass under current node
	`None=`dataclasswrite`(data-class:I)`
	$\rightarrow$ The 'data-class' is a 'DataClass' enumerate.
exponentsinfo	Get the exponents datatype
	`datatype:I=`exponentsinfo`()`
	$\rightarrow$ Python only handles double. Beware at write time, youcan have double/single.
dataclassread	Get the dataclass under current node
	`data-class:I=`dataclassread`()`
	$\rightarrow$ See 'dataclasswrite' remarks.
unitswrite	Create or update a units set under current node
	`None=`unitswrite`(mass-u:S,length-u:S,time-u:S,temp-u:S,angle-u:S)`
	$\rightarrow$ See remarks about the constants dictionnary, one can either use thedefined strings, variables or their enumerates.should be much more documented/checked here
exponentsread	Get the exponents values
	`(D,D,D,D,D)=`exponentsread`()`
	$\rightarrow$ See 'exponentswrite' remarks.
conversioninfo	Get the conversion datatype
	`datatype:I=`conversioninfo`()`
	$\rightarrow$ Python only handles double. Beware at write time, youcan have double/single.