code: def add(
          self,
          symbol,
          base_value,
          dimensions,
          tex_repr=None,
          offset=None,
          prefixable=False,
      ):
          
          from unyt.unit_object import _validate_dimensions
  
          self._unit_system_id = None
  
          # Validate
          if not isinstance(base_value, float):
              raise UnitParseError(
                  "base_value (%s) must be a float, got a %s."
                  % (base_value, type(base_value))
              )
  
          if offset is not None:
              if not isinstance(offset, float):
                  raise UnitParseError(
                      "offset value (%s) must be a float, got a %s."
                      % (offset, type(offset))
                  )
          else:
              offset = 0.0
  
          _validate_dimensions(dimensions)
  
          if tex_repr is None:
              # make educated guess that will look nice in most cases
              tex_repr = r"\rm{" + symbol.replace("_", r"\ ") + "}"
  
          # Add to lut
          self.lut[symbol] = (base_value, dimensions, offset, tex_repr, prefixable)
docs: Add a symbol to this registry.
  
          Parameters
          ----------
  
          symbol : str
             The name of the unit
          base_value : float
             The scaling from the units value to the equivalent SI unit
             with the same dimensions
          dimensions : expr
             The dimensions of the unit
          tex_repr : str, optional
             The LaTeX representation of the unit. If not provided a LaTeX
             representation is automatically generated from the name of
             the unit.
          offset : float, optional
             If set, the zero-point offset to apply to the unit to convert
             to SI. This is mostly used for units like Farhenheit and
             Celcius that are not defined on an absolute scale.
          prefixable : bool
             If True, then SI-prefix versions of the unit will be created
             along with the unit itself.