class_docstr: PipelineLoader for Crypto Pricing data
  
  Delegates loading of baselines and adjustments.
class_docstr_tok: ["PipelineLoader","for","Crypto","Pricing","data","Delegates","loading","of","baselines","and","adjustments","."]
code: def __init__(self, data_frequency):
      cal = get_calendar("OPEN")
  
      if data_frequency == "daily":
          reader = None
          all_sessions = cal.all_sessions
  
      elif data_frequency == "minute":
          reader = None
          all_sessions = cal.all_minutes
  
      else:
          raise ValueError(
              "Invalid data frequency: {}".format(data_frequency)
          )
  
      self.data_frequency = data_frequency
      self.raw_price_loader = reader
      self._columns = TradingPairPricing.columns
      self._all_sessions = all_sessions
  
file_path: catalyst/catalyst/exchange/exchange_pricing_loader.py
imports: from catalyst.constants import LOG_LEVEL
  from catalyst.data.us_equity_pricing import BcolzDailyBarReader
  from catalyst.errors import NoFurtherDataError
  from catalyst.exchange.utils.factory import get_exchange
  from catalyst.lib.adjusted_array import AdjustedArray
  from catalyst.pipeline.data import DataSet, Column
  from catalyst.pipeline.loaders.base import PipelineLoader
  from catalyst.utils.calendars import get_calendar
  from catalyst.utils.numpy_utils import float64_dtype
  from logbook import Logger
  from numpy import iinfo, uint32
label_desc: Use image node_id 1 to create a new ExchangePricingLoader object from inherited base classes: PipelineLoader with example: obj = ExchangePricingLoader(data_frequency)