code: def ensure_is_date_object(x):
      
      error_msg = f"Cannot convert input to date object: {x} (type: {type(x)})"
  
      if isinstance(x, dt.date):
          if isinstance(x, pd.Timestamp):
              if x.freq != 'D':
                  raise TohuDateError("Pandas Timestamp must have freq='D' set. Got: freq={x.freq!r}")
              elif pd.Timestamp(x.date()) == x:
                  return x.date()
              else:
                  raise TohuDateError(error_msg)
          elif isinstance(x, dt.datetime):
              raise TohuDateError(error_msg)
          else:
              return x
      elif isinstance(x, str):
          return parse_date_string(x)
      else:
          raise TohuDateError(error_msg)
docs: Ensure input represents a valid date and return the corresponding `datetime.date` object.
  
      Valid inputs:
  
        - string of the form "YYYY-MM-DD"
        - dt.date object
        - pd.Timestamp of the form "YYYY-MM-DD 00:00:00" with freq='D' (as is generated by pd.date_range())