code: def to_type(self, dtype: type, *cols, **kwargs):
          
          try:
              allcols = self.df.columns.values
              for col in cols:
                  if col not in allcols:
                      self.err("Column " + col + " not found")
                      return
                  self.df[col] = self.df[col].astype(dtype, **kwargs)
          except Exception as e:
              self.err(e, "Can not convert to type")
docs: Convert colums values to a given type in the 
          main dataframe
  
          :param dtype: a type to convert to: ex: ``str``
          :type dtype: type
          :param \*cols: names of the colums
          :type \*cols: str, at least one
          :param \*\*kwargs: keyword arguments for ``df.astype``
          :type \*\*kwargs: optional
  
          :example: ``ds.to_type(str, "mycol")``