diff --git a/micov/_constants.py b/micov/_constants.py
index 6e62962..b43a187 100644
--- a/micov/_constants.py
+++ b/micov/_constants.py
@@ -5,9 +5,9 @@
 COLUMN_SAMPLE_ID = "sample_id"
 COLUMN_SAMPLE_ID_DTYPE = str
 COLUMN_START = "start"
-COLUMN_START_DTYPE = pl.UInt32
+COLUMN_START_DTYPE = pl.datatypes.UInt32
 COLUMN_STOP = "stop"
-COLUMN_STOP_DTYPE = pl.UInt32
+COLUMN_STOP_DTYPE = pl.datatypes.UInt32
 COLUMN_READ_ID = "read"
 COLUMN_READ_ID_DTYPE = str
 COLUMN_FLAG = "flag"
@@ -15,11 +15,11 @@
 COLUMN_CIGAR = "cigar"
 COLUMN_CIGAR_DTYPE = str
 COLUMN_LENGTH = "length"
-COLUMN_LENGTH_DTYPE = pl.UInt32
+COLUMN_LENGTH_DTYPE = pl.datatypes.UInt32
 COLUMN_TAXONOMY = "taxonomy"
 COLUMN_TAXONOMY_DTYPE = str
 COLUMN_COVERED = "covered"
-COLUMN_COVERED_DTYPE = pl.UInt32
+COLUMN_COVERED_DTYPE = pl.datatypes.UInt32
 COLUMN_PERCENT_COVERED = "percent_covered"
 COLUMN_PERCENT_COVERED_DTYPE = float
 COLUMN_NAME = "name"