text: """Abstract Validation class."""
  from abc import ABC, abstractmethod
  
  from pyspark.sql.dataframe import DataFrame
  
  
  class Validation(ABC):
      """Validate dataframe properties.
  
      Attributes:
          dataframe: data to be verified.
  
      """
  
      def __init__(self, dataframe: DataFrame = None):
          self.dataframe = dataframe
  
      def input(self, dataframe: DataFrame) -> "Validation":
          """Input a dataframe to check.
  
          Args:
              dataframe: data to check.
  
          """
          self.dataframe = dataframe
          return self
  
      @abstractmethod
      def check(self) -> None:
          """Check validation properties about the dataframe.
  
          Raises:
              ValueError: if any of the verifications fail.
  
          """
  