code: def add_intercept(X):  # noqa: F811
      columns = X.columns
      if "intercept" in columns:
          raise ValueError("'intercept' column already in 'X'")
      return X.assign(intercept=1)[["intercept"] + list(columns)]
  
file_path: dask-ml/dask_ml/linear_model/utils.py
imports: import dask.array
  import dask.dataframe
  import numpy
  from multipledispatch import dispatch
label_desc: Use image node_id 8 for calling a global function with example usage: add_intercept(X) and returns: X