'Return a new Column instance which is consistent with the
input ``cols`` and has ``length`` rows.
This is intended for creating an empty column object whose elements can
be set in-place for table operations like join or vstack.
Parameters
cols : list
List of input columns
length : int
Length of the output column object
metadata_conflicts : str (\'warn\'|\'error\'|\'silent\')
How to handle metadata conflicts
name : str
Output column name
Returns
col : Column (or subclass)
New instance of this class consistent with ``cols``'

def new_like(self, cols, length, metadata_conflicts=u'warn', name=None):

    attrs = self.merge_cols_attributes(cols, metadata_conflicts, name, (u'meta', u'unit', u'format', u'description'))
    return self._parent_cls(length=length, **attrs)
