code: def get_dimension_type(self, dim):
          
          dim = self.get_dimension(dim)
          if dim is None:
              return None
          elif dim.type is not None:
              return dim.type
          elif dim in self.vdims:
              return np.float64
          return self.interface.dimension_type(self, dim)
docs: Get the type of the requested dimension.
  
          Type is determined by Dimension.type attribute or common
          type of the dimension values, otherwise None.
  
          Args:
              dimension: Dimension to look up by name or by index
  
          Returns:
              Declared type of values along the dimension