code: def size_series(df):
      op = DataFrameSize(output_types=[OutputType.scalar])
      return op(df)
  
file_path: mars/mars/dataframe/reduction/reduction_size.py
imports: from ...None import opcodes
  from ...core import OutputType
  from .core import DataFrameReductionOperand, DataFrameReductionMixin
label_desc: Use image node_id 1 for calling a global function with example usage: size_series(df) and returns: op