title: Error 'Trial_Writing.csv' is not absolute! All paths must be absolute
body: <p>I am trying to Structuring Data from Cell Cycler using BEEP(Battery Evaluation and Early Prediction) toolbox in python. The code is as follows:</p>
  <pre><code>import os
  import json
  
  import pandas as pd
  
  from beep.structure import BEEPDatapath
  
  
  class CyclerDatapath(BEEPDatapath):
      COLUMN_MAPPING = {
          &quot;test_time (s)&quot;: &quot;test_time&quot;,
          &quot;steptime&quot;: &quot;step_time&quot;,
          &quot;stepix&quot;: &quot;step_index&quot;,
          &quot;cycle_index&quot;: &quot;cycle_index&quot;,
          &quot;current (a)&quot;: &quot;current&quot;,
          &quot;voltage (v)&quot;: &quot;voltage&quot;,
          &quot;charge_capacity (ah)&quot;: &quot;charge_capacity&quot;,
          &quot;discharge_capacity (ah)&quot;: &quot;discharge_capacity&quot;,
          &quot;charge_energy (wh)&quot;: &quot;charge_energy&quot;,
          &quot;discharge_energy (wh)&quot;: &quot;discharge_energy&quot;,    
      }
  
      DATA_TYPES = {
          &quot;test_time&quot;: &quot;float64&quot;,
          &quot;step_time&quot;: &quot;float32&quot;,
          &quot;step_index&quot;: &quot;int32&quot;,
          &quot;cycle_index&quot;: &quot;int32&quot;,
          &quot;current&quot;: &quot;float32&quot;,
          &quot;voltage&quot;: &quot;float32&quot;,
          &quot;charge_capacity&quot;: &quot;float64&quot;,
          &quot;discharge_capacity&quot;: &quot;float64&quot;,
          &quot;charge_energy&quot;: &quot;float64&quot;,
          &quot;discharge_energy&quot;: &quot;float64&quot;,
      }
      @classmethod
      def from_file(cls, filename, metadata_path=None):
  
          data = pd.read_csv(filename)
          data.rename(columns=cls.COLUMN_MAPPING, inplace=True)
          print(1)
          
          
          for column, dtype in cls.DATA_TYPES.items():
              if column in data:
                  if not data[column].isnull().values.any():
                      data[column] = data[column].astype(dtype)
  
          if metadata_path:
              print(1)
              with open(metadata_path, &quot;r&quot;) as f:
                  metadata = json.load(f)
          else:
              metadata = {}
          path = filename
   
          paths = {
             &quot;raw&quot;: path,
             &quot;metadata&quot;: path + &quot;_metadata&quot;
         }
  
          return cls(data, metadata, paths)
      
      
      from beep.structure import NewareDatapath
  
  
  cycler_file = (&quot;Trial_Writing.csv&quot;)
  
  datapath = CyclerDatapath.from_file(cycler_file)
  
  datapath.to_json_file(&quot;my_processed_neware_data.json&quot;)
  </code></pre>
  <p>I get an error as follows:</p>
  <pre><code>`ValueError: raw: 
    File &quot;C:\base.py&quot;, line 181, in __init__
      raise ValueError(f&quot;{path_ref}: '{path}' is not absolute! All paths must be absolute.&quot;)
  </code></pre>
  <p>I tried to debug that code and found that the code works fine till here:</p>
  <pre><code>  # Read in metadata from a separate json file, for example
              if metadata_path:
                  print(1)
                  with open(metadata_path, &quot;r&quot;) as f:
                      metadata = json.load(f)
  </code></pre>
  <p>After this point i get the error.</p>
  <p>Anyone with knowledge in BEEP library knows what I am going wrong?</p>